Natural Weed Control

By Philip A. Wheeler, Ph.D.

There are many ways for growers to implement non-toxic weed control methods on their farms. The most obvious is to take the chemical farming approach and find an organically-approved material to do the killing. Very strong vinegar has been the most marketed material. The important factor in vinegar formulas is to include a surfactant to strip away any waxy protective coating on the plant surface to allow the desiccation (drying out) of the plant. Salt provides the same mode of action and may be included in the formula.

Other modern mechanical approaches to weed control include flaming, cultivating, and smothering. Cultivators are a modern version of hoeing or hand pulling. Rotary hoes or spiked harrows are special adaptations of the cultivation approach. Using plastic films, whether biodegradable or not, is a form of smothering that is similar to mulching with any material. The cover denies sunlight to prevent growth.

Repeated cuttings of a perennial weed in a fallow field may weaken a plant over time by using up its stored energy. Farmers should also make every attempt to prevent the reseeding of an offending species. Treating isolated patches is worth the effort to keep them from spreading. If a field is overwhelmed to a point of not having an economic crop worth harvesting, be sure to take the whole field down before the weeds go to seed. Keep in mind that there are seeds in your fields that may have been there for years. Just lime or activate the calcium in your soil and watch clover appear in uncultivated ground, even if you haven’t seeded it since you bought the farm.

By the same token, there are all kinds of weed seeds that are just laying there, waiting for you to damage your soil to a point where they can spring out. Weeds also wait for you to use a herbicide to suppress one of your current weeds, which has been keeping another weed you weren’t even aware of under control. Nature knows what she is doing!

Improving Soil for Weed Control

A more natural form of weed control is to activate the forces of nature by crop rotation, which allows the allopathic properties of each subsequent crop to affect the soil. Cover cropping is usually a more direct attempt to apply the specific beneficial properties of a given cover crop to the specific weed problem. Online sources of research are readily available to match specific cover crops to specific weeds. I have always recommended the use of a mixture of two or three plant species for cover cropping, and articles have recently appeared that report that mixtures of ten to fifteen species are providing even better weed suppression and soil health.

The allopathic effect of the economic crop can be amplified by cross-drilling small grains. During my organic farming days I used a little more than half the normal seeding rate and then drilled a north-south pattern followed by an east-west pattern. This increased the soil area impacted by the economic crop to almost total coverage within the field. The results were spectacular, especially considering the previous corn crop had been infested with redroot pigweed that had gone to seed.

man on tractor — The primary condition that promotes broadleaf weeds is the ratio of available phosphorus to available potassium, as shown by a LaMotte soil test. The further you deviate from a 1:1 ratio, the stronger the broadleaf pressure.

Since all weed and grass germination is a function of soil and weather conditions, the most natural way to accomplish weed control is by soil mineralization and bioactivation.

The accumulation of knowledge from the last hundred years of research has provided us the standard Cation Exchange Capacity (CEC) model to aim for on our fields. You will find variations between labs and consultants, but don’t let that discourage you from taking tests and using them as a guide to begin balancing your soil for the purpose of production of nutrient-dense crops, with the added benefit of discouraging weed and grass pressure.

Achieving a soil that is so perfectly balanced and biologically active as to not have any weed or grass pressure is difficult, but not impossible. Dr. Rahm taught that the primary condition that promotes broadleaf weeds is the ratio of available phosphorus to available potassium, as shown by a LaMotte soil test. The further you deviate from a 1:1 ratio, the stronger the broadleaf pressure. In the 1970s, an associate of mine, Joe Scrimger, had a place on his farm where the usual herbicides totally failed to control the typical weeds he had in other fields. We performed LaMotte tests and compared the bad spot to a typical field. In his fields where the herbicide gave reasonable control, the ratio of P to K was 1:4. In the area where the herbicides failed, the ratio was 1:8. The weeds in that area were so healthy and strong that they could overcome the toxic effects of an herbicide applied at the usual rates.

I have regretfully discovered that excess wood ash, which is high in available potassium, is a sure way to have uncontrollable weeds in my farm garden. I have also noticed that areas receiving raw manure are prone to redroot pigweed and lambsquarter — aka, “fertility weeds.” It is now generally understood that broadleaf weeds thrive on diets of highly available nitrate and potassium. In standard NPK fertilizers, potassium is much more available than phosphorus due to its dependence on biological activity and its propensity to chemically bind with calcium. That bonding reduces the available calcium in your soil, increasing the pressure for Mother Nature to germinate a sour grass such as quack or crabgrass to bring calcium to the surface. In other words, NPK farming promotes weeds and grasses, increases your “rescue chemistry” costs, and lowers the value of your crop.

Another way of verifying that you are fertilizing for weeds is to measure the Brix of the weeds and of the cash crop. If the Brix of the weed is higher than the economic crop, then obviously the weed is healthier/stronger than the economic crop. The logical conclusion is that your fertilizer program favored the weeds rather than the crop you were trying to harvest and sell. If you were intending to make corn silage, it could ironically turn out that the feed value of your silage would be higher with more high-Brix broadleaf weeds than with less.

Oats cover crop for weed control — The most natural way to accomplish weed control is by soil mineralization and bioactivation.

Organic and sustainable growers can fall victim to the same phenomenon as conventional NPK farmers when they apply raw or partially-composted manures, organically approved Chilean Nitrate (NaNO3), or any other soluble nitrate, sodium, or potassium source. Even if they have applied a natural phosphate, failure to insure mycorrhizal inoculation and general bioactivation can lead Mother Nature to think that the ratios are still off.

Most of the weed problems in farming are surface problems. Each time the soil is disturbed, new weed seeds come to the surface, rays of sunlight strike them, and they germinate if the other soil signals tell them it is their turn to come out. This relation to sunlight exposure led to another weed control approach: cultivating or planting at night with hooded or red headlights to avoid the sunlight-triggering response.

Because of GMOs, we now also have to add the factor of herbicide resistance. According to the March 2013 issue of The Furrow, Arkansas farmers had to hand hoe up to 52 percent of the state’s cotton acreage at a cost of $30 per acre.

Weed Control: Results in the Field

I first learned of the successful use of liquid calcium and molasses for surface weed control in the early eighties. At about the same time I learned that oats were a good accumulator of phosphorus and that winter-killed oat crop residue provided both allopathic suppression as well as additional bio-available phosphorus. After writing about this in my newsletter, a Pennsylvania farmer reported a very successful and weed-free, no-till corn crop by planting a heavy fall cover of bin-run oat seed, letting it winter-kill, and then no-till drilling his corn seed into the residue. He also added the liquid calcium and molasses spray right after planting. The net effect was a weed-free field of organic corn.

The next report we received was from a strawberry grower. For those of you who have come by our booth at an Acres U.S.A. conference, the sequential pictures show the amazing total suppression of weeds and grasses in what amounts to open soil between the rows of strawberries for an entire season. The grower planted a heavy crop of fall oats in Pennsylvania. Naturally, they winter-killed. After tilling them in, he planted his rows of strawberries. Following the correct procedure, he sprayed a liquid calcium and molasses mixture at a slightly reduced rate. Since this was a U-pick operation, he repeated his calcium-molasses spray at about one-quarter rate every few weeks as he was getting soil disturbance from customers. The net effect was almost perfect weed control without the use of any mulch, any mechanical removal of weeds, or any toxic spray.

Scores of growers have since tried this concept on every imaginable crop. At first the two-gallon liquid calcium part of the formula was applied as non-organic chelated calcium nitrate or organic chelated calcium chloride, along with the two gallons of molasses. The molasses is critical to the formula as it feeds/activates the phosphatase bacteria that break the bonds of tied-up phosphorus. A few years ago, two alternative sources of calcium came on the market: limestone ground to five hundred mesh and Tennessee Brown phosphate that contains both calcium and phosphorus ground to five hundred mesh. Both are available as liquid suspensions (Premium Cal 33 and Phos Cal 22) for easy mixing and blending.

The latest test of the formula came in 2013 on a California organic rice farm. A Lundberg Farms contract grower used these procedures and materials to achieve control of water grass on ninety-two acres of short-grain rice. As the last disturbance of soil was leveling, they applied the weed suppression formula of two gallons of molasses and forty-two ounces per acre of Phos Cal 22 (we had recommended sixty-four ounces per acre, but the final rate was more of a factor of, “we have this much product and this much acreage to cover”) in twenty gallons of water applied by ground rig. They took the additional step of using drop nozzles to insure a uniform coating on the soil. A few days later, they flooded the field and then seeded by air. The results were excellent.

The local flying service reported that the organic field had equal or better control than the chemical fields in the area. The yield was five thousand pounds per acre, at a weed control cost of less than $20 per acre!

This article appeared in the March 2014 issue of Acres U.S.A.

Philip Wheeler is a crop consultant and lecturer who has worked with growers all over the world. He can be contacted at Crop Services International Inc. or 616-246-7933. The Non-Toxic Farming Handbook, by Philip A. Wheeler and Ronald B. Ward, is available from the Acres U.S.A. bookstore.

Organic Weed Control: Cultural and Mechanical Methods

By Howell and Klaas Martens
From the August 2002 issue of Acres U.S.A. magazine

Organic weed control methods are often debated and dismissed by large chemical sprayers. But organic weed control methods do work, and work better for your field’s health.

Weeds happen. That is a fact of life for organic farmers, and therefore many of our field operations are designed to make sure that the health and quality of our crops are not jeopardized by the inevitable weed pressure.

Planning an effective weed-control program involves many different aspects of organic crop production. As farmers begin to explore organic possibilities, the first two questions invariably seem to be: “What materials do I buy for soil fertility?” and “What machinery do I buy to control weeds?” We asked these questions when we started organic farming, but we rapidly realized that this is not the best way to understand successful organic farm management.

To plan an effective weed-control program, you must integrate a broad spectrum of important factors, including your soil conditions, weather, crop rotations and field histories, machinery, markets and specific market quality demands, and available time and labor. You must have the ability to adjust your weed-control strategies to the unique and ever-changing challenges of each year. Above all, you must be observant, and, in the words of William Albrecht, you must learn “to see what you are looking at.”

Cultural Organic Weed Control

Do you think that weeds just happen, that there is little you can do to limit your weed population other than cultivate? Then think again! Before you even think about cultivating, there are many things that you can actively do to change field conditions so that they favor crop growth and discourage weed pressure. Cultural weed control is a multi-year, whole-farm, multi-faceted approach — and you are probably doing much of it already without realizing the effect your actions have on weed pressure.

Writing in 1939, German agricultural researcher Bernard Rademacher stated, “Cultural weed control should form the basis for all weed control,” and that “the other various means should be regarded as auxiliary only. The necessary condition for any successful weed control is the promotion of growth of the crop species. Vigorous plant stands are the best means for eradicating weeds.” The same wisdom must be applied to organic agriculture today, actively incorporating the philosophy that good agronomic practices that result in vigorous, competitive crop plants are the real key to successful weed control.

Many agronomic procedures that encourage healthy soil conditions with a diverse microbial population can also reduce weed pressure. Optimizing the biological terrain of the soil — the life in the soil — for the crop will create an unfavorable environment for many weeds, effectively reducing weed numbers and vigor. This concept forms the core of effective weed control in an organic production system.

Contrast this to the weed-control strategies of conventional farming, with heavy use of salt fertilizers, herbicides, monoculture and imbalanced cation saturations.

Indeed, that environment could accurately be described as one of cultural weed enhancement. The conventional field environment presents heavy pressure to select for herbicide-resistant weeds that thrive under these conditions. Each year, these highly adapted weeds find the same favorable conditions and reproduce abundantly. It is really no wonder that most herbicides are only effective for a few years before a newer, stronger (and more expensive) chemical is needed to control weeds sufficiently.

It is important to know your enemy. All weed species have their weaknesses and their strengths, usually occurring at distinct stages of their life cycles or resulting from specific growth patterns. Different weeds present problems at different times of year, or with different crops. Some weed-control strategies, such as disking a field infested with quackgrass, may even increase the prevalence of certain species of weeds under specific conditions. Grassy weeds often require different control measures than do broad-leafed weeds. Correctly identifying the species of weeds that are causing major problems in your fields is critical to choosing and timing effective control measures. It is valuable to have a good weed-identification book and use it regularly during the season until you are confident recognizingyour most common and troublesome weeds.

While no factor can truly be viewed as separate, it is important to examine some of the primary management concepts that contribute to effective cultural weed control.

Crop Competition. The most effective way to control weed growth is to have highly competitive crops. A vigorously growing crop is less likely to be adversely affected by weed pressure. It is imperative to create conditions where the intended crop can establish dominance quickly. Using high-quality, vigorous seed, well-adjusted planting equipment, adapted varieties, optimal soil fertility, good soil drainage and tilth, and proper soil preparation will usually result in rapid, vigorous crop growth.
Soil Fertility and Condition. In an organic system, it is important to rely on the biological activity of the soil as the main source of fertility and favorable soil physical structure. An active and diverse soil microbial population is the key to growing healthy, high-yielding organic crops. Successful organic fertility management should primarily feed the soil ecosystem in a long-term manner, rather than simply feeding the plants. Soil organic matter is a tremendous source of plant nutrients and water-holding capacity. Soil tests can be useful, but only if the results are interpreted appropriately for an organic system. Careful attention to the balance of key nutrients can often reduce weed problems and enhance crop plant growth. One common mistake made by many organic farmers is the improper application of manure or improperly finished compost. This can throw off the balance of certain soil nutrients and microbial life and can often increase weed growth. Some soil fertility amendments, such as gypsum, can increase the looseness and tilth of the soil. This improves success for mechanical-cultivation operations, but it also seems to reduce the pressure from certain weed species that are favored by hard, tight soils.
Crop Rotation. Diverse crop rotations are essential to build a healthy, sustainable organic system and break pest and weed cycles. In general, it is best to alternate legumes with grasses, spring-planted crops with fall-planted crops, row crops with close- planted crops, heavy feeders with light feeders. Careful use of cover crops during times when the ground would be bare adds valuable nutrients (especially nitrogen), adds organic matter, improves soil microbial diversity, and prevents erosion. Maintain a long-term balance of diverse crops on a farm, taking into account any necessary soil conservation practices, livestock requirements, time constraints and market profitability.
Allelopathy. Some plant species compete with each other by releasing chemical substances from their roots that inhibit the growth of other plants. This “allelopathy” is one of nature’s most effective techniques of establishing plant dominance. Allelopathic crops include barley, rye, annual ryegrass, buckwheat, oats, sorghum, sudan-sorghum hybrids, alfalfa, wheat, red clover and sunflower. Selecting allelopathic crops can be useful in particularly weedy fields with reducing overall weed pressure.
Variety Selection. Careful selection of crop varieties is essential to limit weeds and pathogen problems and satisfy market needs. It is important to consider planting disease-resistant varieties if certain pathogens are prevalent in the area. Any crop variety that is able to quickly shade the soil between the rows and is able to grow more rapidly than the weeds will have an advantage. Deep shading crops, which intercept most of the sunlight that strikes the field and keeps the ground dark, will prevent the growth of many weed species. Alfalfa, clover and grasses are particularly good shading crops because any weeds that grow in them will usually be cut when hay is harvested, thereby preventing weed seed production.
Sanitation. Using clean seed will prevent the introduction of new weed problems and will avoid planting a generous crop of weeds with your desired crop. Mowing weeds around the edges of fields or after harvest prevents weeds from going to seed. Hand-roguing weeds in problem areas, and thoroughly composting manure can reduce the spread of weed seeds and difficult weed species. Thorough cleaning of any machinery that has been used in weedy fields is a good idea, as is establishing hedgerows to limit wind-blown seeds. Common sense, yes — and it works! Cultural practices won’t prevent all weed growth, and some mechanical follow-up will usually be necessary, but cultural practices can improve soil conditions, permitting more effective mechanical control, they can adjust weed species to ones that are easier to control, and, most importantly, cultural weed-control practices can produce high-quality, vigorous, high-yielding organic crops.

Mechanical Organic Weed Control

We like to consider mechanical weed control as consisting of four distinct phases, each one very important to the overall success of your weed control program. The point in early mechanical weed control is to create as large a crop-to-weed size differential as possible, as early as possible, so that row cultivation is most successful. When crop plants are bigger and more vigorous than the weeds, the weed pressure will usually not jeopardize the crop. Therefore, effective early weed control, before weeds present a visible threat to the crop, is absolutely essential.

Tillage

Appropriate tillage of fields is critical:

To create a good seed bed for uniform, vigorous crop emergence.
To prepare the ground adequately for successful subsequent mechanical weed control operations.
To eliminate much of the weed potential.

When it is possible, initial tillage a week or 10 days before planting will allow the resulting flush of germinating weeds to be killed during final field preparation. Organic gardeners call this technique “stale seed bed.” Weed seeds are stimulated to germinate by the first tillage, then they are killed by the second, final field preparation. Many organic farmers find that in heavily infested fields, late spring plowing will reduce weed pressure by killing weeds that have started to grow and burying many germinating weed seeds.

Plowing can have a different positive effect by inverting weed seeds that have started to germinate down deeply where they won’t grow, and bringing other weed seeds that have not yet been stimulated to germinate to the surface. By the time these new weed seeds “get the message” to germinate, you can already have your crop growing.

It is important to note that weather conditions dictate how effective tillage is in controlling weeds. Naturally, the best weed control will be achieved with tillage on a hot, sunny day. Tilling soil that is too wet will result in compaction and loss of soil structure, which will then favor certain types of weeds that prefer hard ground and will also make later cultivation less effective. Wet weather following tillage may result in weeds re-rooting. Cold, wet conditions following initial tillage may also slow weed seed germination, reducing the effect of stale seed bed.

If the soil breaks up into large clods when plowing, weed seedlings may be protected within the clods and not killed by the tillage. If the ground is worked wet, and clods are formed during tillage, this will make subsequent mechanical weed control much more difficult.

When tillage is done on a sunny, warm day, troublesome weeds with long underground rhizomes, such as quackgrass, can be dragged to the surface and will dry out. Dragging a field with a spring tooth harrow can pull many of these rhizomes to the surface. This old technique can effectively rid an infested field of quackgrass if done several times.

To Till or Not to Till — that seems to be the burning question in American agriculture these days. Excessive tillage can result in soil erosion, breakdown of soil structure, a shift in microbial activity and loss of organic matter, and it uses considerable amounts of fuel and tractor time — this does not mean you should go out and invest in massive quantities of Roundup, however. Sometimes it seems that the current popular infatuation with no-till often amounts to little more than institutionalized support of Monsanto’s profits. Not all soils, not all crops, and not all farms are well suited to no-till. After all, there is a well-known saying here in New York: “No till, no corn!”

Organic farmers can and should incorporate reduced tillage practices into their techniques. You do not have to plow every year, nor do you have to use herbicides to get the benefits of reduced tillage. Many crops — such as small grains, clover and grass hay — can be successfully planted in untilled or lightly tilled soil. Anne and Eric Nordell in Pennsylvania are no-till planting garlic into growing oats in the fall. The oats winterkill, forming a thick mulch that prevents weed problems in the garlic in the spring. Planting into a living crop, like the oats, provides continuous physical cover to the soil, and there is less soil damage by winter rains and snow than if the ground were bare. This helps maintain good soil pore space and healthy microbes during a vulnerable period for the soil.

There are many creative ways that organic farmers can incorporate reduced tillage into their operations, but we should not feel guilty about occasional plowing. Mixing the soil will redistribute nutrients and make them available to crop plants. The introduction of air into the soil is also important, especially in an organic system that relies on microbial activity to provide soil fertility. With the introduction of new oxygen, the soil microbes are able to digest soil organic matter, to convert it into stable humus, and to reproduce, releasing readily available nutrients into the soil solution which our crops will use. While some soil organisms may be harmed by the physical action of plowing, for many species and for plant roots this breath of fresh air is just what they’ve been waiting for. To organic farmers, the most important value of soil organic matter is its use as a source of fertility — and our friends the microbes need oxygen to do that.

The most successful no-till systems that we know of are actually being “bio-tilled,” using plant roots and animals like earthworms to actively till the soil instead of machinery. We have fairly good success with no-till broadcasting small grains, like spelt and wheat, into fields of living soybeans in early fall. The grains are well started by the time the soybeans are harvested. This success is consistent with other successful organic no-till systems we’ve seen, where a new crop is planted into a still-living old crop, and where there are living roots and active soil microbial conditions. This is a much different biological environment than when a broad-spectrum herbicide is used to kill all living plant material in the field, and the ground is left bare over winter.

“Carbon sequestration” is a real buzzword in conventional ag circles, the justification for promoting no-till/Roundup technology. If all you want to do is sequester the maximum amount of carbon in your soil and raise your soil organic matter, then burying fence posts would probably be your best bet. However, if you want the soil organic matter to be an active source of fertility and to support an active, diverse microbial population, then these tiny aerobic (oxygen-needing) organisms need air. Both Sir Albert Howard and Neal Kinsey have observed that there is a rapid loss of soil organic matter after soil becomes anaerobic due to excessive water or compaction. Plowing adds new air to the soil, releases the buildup of waste gases, mixes nutrients and organic material around in the soil, and when the plowing is not so excessive as to cause compaction, it helps to loosen soil and produce good soil-pore space for air and water holding capacity.

Remember that where no-till techniques are used, subsequent mechanical weed control options are more limited because of trash and because the soil may not be loose enough. Therefore, it is really critical to have your cultural weed control strategies in good shape before trying any no-till options.

Planting the Crops

Few farmers realize that a well adjusted planter is one of their most valuable weed control tools. Uniform, proper placement of the crop seed will result in even vigorous growth. Don’t assume that just because a planter has shiny paint, it is doing a good job! And remember to use cleaned, high-vigor seeds for rapid, strong emergence.

You should regularly get off the tractor and dig up the seed to check the accuracy of the planting and make adjustments if necessary. This should be done not only in the good locations in the field but also in lumpy, uneven or unusual areas too. Planting into wet or particularly lumpy soil should be avoided. Older corn planters with worn seed discs, gauge wheels, closing wheels or other parts can result in uneven planting. Worn parts should be replaced or repaired.

The planter frame and units should also be regularly inspected to insure they are not bent or warped. Retrofitting with shoes, firming points, specially designed seed tubes or “eccentrically” (on an angle) bored gauge wheel bushings will often result in more uniform seed placement than what the planter had when it was new. Trash wheels in front of the gauge wheels will sweep away clods and stones, making for a level surface and therefore uniform planting.

Blind Cultivation

“Blind cultivation” is the easiest and best opportunity to destroy the weeds that would be growing within the rows and presenting direct competition to the crop. In blind cultivation, the entire field is tilled shallowly with the implement, paying little attention to where the rows are. The point of blind cultivation is to stir the top 1 to 2 inches of soil, adding air and causing the millions of tiny germinating weed seeds to dry out and die. The larger crop seeds germinate below the level of the cultivation and are not usually damaged by this operation. Weed seedlings are very vulnerable to drying out and to burying at this stage, and by doing an effective job of blind cultivation, you can achieve the biggest possible crop/weed size differential from the start. Blind cultivation also can break a soil crust, allowing crop seedlings to emerge.

Usually, the first blind cultivation pass is done right before crop emergence, with a second pass done about a week later, depending on conditions. The most effective blind cultivation is done when the soil is fairly dry and the sun is shining, a wind also improves the effect.

There are a number of implements that can be used for blind cultivation. Coil-tine harrows, rotary hoes, Lely weeders and Einböck tine harrows are some examples of useful tools that organic crop farmers use.

The Kovar coil-tine harrow has either regular straight tines, or new tines that are bent on the ends and the angle to the soil can be adjusted changing the aggressiveness.

A 45-foot Kovar coil-tine harrow can actually cover the fields faster than a sprayer would and is very economical to operate.

Some organic farmers prefer to use the rotary hoe, going over the field the first time about three to four days after planting, and again five days later. Speed is a key factor in successful rotary hoe operation. A rotary hoe needs a high-horsepower tractor capable of moving at least 8-12 mph to be effective. Surprisingly, this does little damage to the young crop seedlings but destroys germinating weeds fairly effectively.

The Lely weeder works similarly by shaking the soil loose — killing small weeds but not harming the larger, deeperrooted soybeans. The Lely weeder is very effective in breaking a surface soil crust. Do note, however, that the Lely can be rough on corn seedlings if it hooks the corn’s branching root system.

There are other implements that do the same job of blind cultivation, such as the Einböck tine weeder. It pays to have several different tools on hand, so you can match the best tool to changing soil and crop conditions.

It is not uncommon to find inexpensive old, worn rotary hoes at auctions. Are they a good deal? Long before you think a rotary hoe is worn out, the teeth may be shorted, rounded and much less aggressive than new teeth. Such a rotary hoe will barely penetrate the ground properly, resulting in less dirt moved and few weeds killed. A good rotary hoe can be an expensive machine to maintain, but it is not essential to replace all the worn rotary hoe teeth.

Since weeds growing between the rows will be controlled by later cultivation, you can economize by installing new rotary hoe wheels only directly over each row and leaving older wheels between the rows. Hoe bits can be welded to worn rotary hoe teeth to extend the life of the machine.

Weed species vary in their vulnerability to blind cultivation. Broad-leafed weed seedlings with their growing point above ground are easily killed when their tops are broken, while grasses with growing points below the soil surface need to be uprooted and desiccated. Most weeds are most sensitive to desiccation when they are in the “white hair” stage, early in germination. Established perennial weeds with deep roots and large reserves are not well controlled by blind cultivation and must be controlled by other methods.

Pounding rains can seal the surface of the ground, causing a crust to form. This problem can be especially troublesome on high magnesium or clay soils. Germinating crop seeds, especially legumes, can be trapped under the crust, unable to emerge or “breaking their necks” while trying to get through. A soil crust can also stimulate the germination of certain types of weeds. Ellen Chirco, seed technologist at the New York Seed Testing Laboratory, says that seeds of some plant species are stimulated to germinate by a buildup of carbon dioxide and ethylene in the soil, which results from improper air exchange and anaerobic conditions. Running a blind cultivation tool, like the coil-tine harrow or rotary hoe, through the field as a crust starts to form will often stop the hardening and thickening of the crust, allow crop seedlings to emerge, release some of the carbon dioxide and ethylene, let oxygen into the ground, and thereby slow the germination of some types of weeds.

Between-Row Cultivation

Effective early weed control, before weeds present a visible threat to the crop, is absolutely essential. The late-season weed control operations should be viewed as a follow-up, not as your primarily weed control. However, there are usually some escapes, and sometimes, unfortunately, there are lots of escapes. That’s when it’s time to set your cultivator correctly, drive straight and slow, and really pay attention to the details.

When the crop rows are clearly visible and the corn plants are 8 to 10 inches tall — or soybeans are in the third trifoliate stage — it is time for between-row cultivation. Earlier cultivation may be necessary if a good crop/weed size differential has not been achieved, especially if weather has prevented your early season weed-control operations to be done optimally, but cultivation will go much slower and less aggressively when the plants are small because it is important to prevent the crop plants from being buried. In New York, two cultivation passes are usually required. The first pass is the most critical to determine the season’s weed control, but the second is often necessary to eliminate the weeds that were stimulated to grow by the first cultivation, and to further aerate the soil.

There are rear-mounted and front- or belly-mounted models, and there are numerous types of cultivator teeth, shanks and points. Some farmers have tractors equipped with only a rear-mounted cultivator, while others get good control with a tractor equipped with both a front- and rear-mounted cultivator.

There are three main types of cultivator shanks:

Danish- or S-tine teeth will allow the greatest operating speed, they are not easily damaged by rocks, they will handle the most crop residue without plugging, and they are relatively inexpensive. They do not penetrate as well in hard soil, however, and large rooted weeds may slip around the flexible teeth, thereby avoiding damage. Of different types of cultivator teeth, the operator has the least control over the action of the flexible Danish-tine teeth.

C-shank cultivator teeth are more rigid and give the operator more control. These may be the best for hard or rocky soil and for heavy infestations of quackgrass and other weeds with underground rhizomes. C-shank teeth are slightly more adjustable than the Danish-tine teeth. Trip-shank teeth are the most rigid and require the slowest progress, but they give the operator superior weed control and adjustment ability. These are also the most expensive, large rocks can break the trip-shanks, and it takes a more experienced operator to make the necessary adjustments to get the full benefit of trip-shank teeth.

There are many different types and widths of points that can be put on different cultivator teeth. Danish-tine teeth offer the least opportunities to vary point type, while trip-shank teeth offer the greatest choice. The most versatile type of points are probably half sweeps next to the row and full sweeps between rows. Each type of point works best under specific conditions and on certain weed species. For example, a type of point called a “beet knife” is particularly effective on nutsedge. Narrow spikes may sometimes be used to advantage to aerate waterlogged soil.

We use a double-cultivator arrangement, with trip-shanks on the front cultivator and half sweeps next to the row. The rear-mounted cultivator, which has C-shank teeth with full sweeps, covers the between-row area. While this combination is slower than a single Danish-tine cultivator, it gives excellent control of most types of weeds, even under an unfavorable crop/weed size differential. John Myer, in Romulus, New York, has had success with a rear-mounted Danish-tine cultivator with five shanks and 2.5-inch duck-feet points between each row. If the ground is hard, or if he has a quackgrass problem, he will instead use 1-inch spikes that are angled back to dig deeper. If he must cultivate when the soybeans are shorter than 7 inches, he will use halfworn teeth immediately next to the row.

Adjusting the cultivator to best fit the conditions is a fine art.

Relatively little adjustment is possible with Danish tines other than varying speed and depth and by changing the type of the points. With C-shanks, it is possible to change the angle to the soil and to the row slightly, but because they are springs, this adjustment changes in the soil as the cultivator moves. This is not a major problem when the cultivator is set deep and working between the rows, but it limits the success of controlling weeds within the rows. Trip-shanks allow wide adjustment of the angle of the points both to the row and to the soil.

Depth of the point is also easily adjusted. Because trip-shanks are rigid, the adjustments remain constant while cultivating. For example, by twisting the shank toward the row, a much greater amount of soil will be pushed into the row.

Conversely, by twisting the shank away from the row, the soil thrown into the row is reduced. Changing the angle of the point to the soil can adjust for hard or soft soil.

Under the right soil conditions, setting the points at an extreme angle to the soil can create a bulldozer effect, squeezing the crop row tightly with soil and thereby killing many weeds growing between the soybean plants and burying the rest.

Another logical but often overlooked point in successful cultivation is suggested by Cliff Peterson, a retired Yates County farmer, who remembers cultivating with horses when he was a boy. For the second cultivation in a field, Cliff suggests reversing the pattern/direction of the first cultivation. This alternating method can get weeds that were not fully removed in the first cultivation, and can compensate for gaps in cultivator coverage.

Plan on spending a lot of time when you first get out in the field adjusting the cultivator to get it to work right for the specific field conditions. As Cliff Peterson says, “Almost isn’t good enough! Don’t be satisfied with almost!” The first time through cultivating makes or breaks it — this pass will usually determine whether you are going to have a clean field or not. If you miss the weeds in the row the first time, cultivating more often later in the season will probably not make up for it.

It’s easy to get the weeds between the rows, but it takes real skill to get the weeds within the row. Cultivating works best when the ground is dry enough and in good physical condition. If you have to cultivate too wet, you can twist a piece of wire around the shovel and that will help break up the slabs of dirt as they flow over the shovel.

Critical Cultivator Adjustments:

Tractor speed — adjust as you go across field.
Angle of the shovels, both laterally and horizontally to the row.
Depth of the shovels.
Down pressure on the gangs, if you have springs — this may need constant adjustment, depending on changing field conditions.
Distance of the shovels from the row.

Adjustments will need to be done continuously through the day, as soil moisture and field conditions change, and as shovels wear or go out of adjustment. All rows need to be watched for adjustment needs. As you move along, watch all the rows, don’t lock in on only one. If you don’t watch all the rows, you can go along quite a distance before you realize something is wrong, by which time you’ve done lots of crop damage and missed lots of weeds. Carry a box of good tools on the tractor to make the adjustments easily and quickly, and carry common repair parts that may be needed. It is essential to really focus on the rows and the job while cultivating, because even a slight drifting in the row can rapidly result in large sections of the corn or bean row being very effectively hoed out. Cultivating can be a very hot, boring job, especially when the crop plants are small. For the sake of the operator’s health and attention span — and the health of the crop! — it makes a lot of sense to install a canopy on the tractor, bring a water bottle, and stop if you get sleepy.

It really helps to work with a farmer who is experienced with cultivating to learn and actually see how the dirt should flow, how much side pressure on the row is best, how much dirt should be pushed into the row to bury the weeds, how to make the proper adjustments, and to learn how hard you can treat the crop without hurting it.

One last word about cultivation and organic weed control: Trying too hard to get every last weed in a field can waste time, labor, and may actually do damage to the crop. Tractor operations after canopy closing will usually crush and tear crop plants excessively — and will probably be unnecessary, as shade from crop leaves will kill weeds trapped under the canopy. It is important to keep the whole crop in perspective, and not spend too much time making the first few fields immaculate.

Weeds — Control without Poisons by Charles Walters

This is an excerpt from Weeds — Control without Poisons, written by Acres U.S.A. founder Charles Walters. In this book, Walters includes specifics on over 100 weeds – small-seeded annual grasses, perennial grasses and sedges, as well as exotics – about why they grow, what soil conditions spur them on or stop them, what they say about your soil, and how to control them without the obscene presence of poisons. All weeds are cross-referenced by scientific and various common names, and a pictorial glossary.

The excerpt below discusses how to observe weeds in the field, and offers suggestions on tactics to control them, plus descriptions of Walters’ visits to other farmers’ fields.

From Chapter 2: Observing Weeds Grow

Andre Voisin, the great French farmer and scientist who wrote Soil, Grass and Cancer and Grass Productivity, once declared that most of what he knew came not from the university, but from observing his cows at grass. And so it is with much of what we know about weeds. Walking the fields with the late C.J. Fenzau in areas as separate as Indiana, Iowa and Idaho, I was able to take note of what weeds were trying to tell us during the early days of the Acres U.S.A. publication. Admittedly, this knowledge has been fleshed out since then. And recent findings build on, rather than tear down, those field observations.

Weeds are an index of what is wrong — and sometimes what is right — with the soil, or at least with the fertility program.

In every field on every farm, there are different soil types, and each has a potential for producing certain weeds, depending on how a farmer works the soil. Fall tillage, spring tillage, tillage early or late, if it takes place when the soil is dry or wet, all these things determine the kinds of weeds that will grow that season.

As far back as the Dust Bowl days, it became transparently obvious to my Dad — after viewing rainbelt territory near Conway, Missouri — that dryland weeds generally don’t grow in territory that has rain pelting the soil with a steady squall. Thus the presence of salt grass, iron weed, tumbleweed and all the wild sages in soils where flocculation is gone, and wind wafts dust skyward.

There are soil conditions that almost always have restricted amounts of water, and consequently they do not require and cannot grow weeds that thrive when there is plenty of water.

In high rainfall areas of the United States, where irrigation is paper thin and where farmers depend on rainfall for their crop moisture, broadleaf weeds — lambsquarters, pigweed, Jimson weed, buttonweed, and so on — often proliferate.

These special conditions appeared classic when C.J. Fenzau and I walked several farms near What Cheer, Iowa one summer.

Where the soil structure was poor and farmers worked the soil under wet conditions, they usually built compaction or set up sedimentary levels in the soil from filtration of silt. This set the stage for a lot of grassy weeds. And in only moments, it seemed, the corn farmer is forced to endure the vicious effects of foxtail and fall panicum.

The soil’s potential might remain. For the season, this pattern of weeds indicates a degenerated soil structure. That’s the signal foxtail and fall panicum send out loud and clear — that there is an imbalanced pH condition in the soil, that tight soil is holding water in excess and refuses to permit it to dry out.

As a consequence, the farmer is always working his soil system on the wet side and creating clods. When he gets done planting fields with clods, they accumulate excess carbon dioxide. Foxtail and fall panicum like carbon dioxide. This triggers certain hormone processes that wake up the foxtail seed and say, It is your turn to live and multiply.

To control the foxtail, it now becomes necessary to change the structure of the soil, and this means tillage, fertility management — not least, pH management, efficient use of water, development of capillary capacity and aeration of the soil. This much accomplished, there is no need for atrazine or other chemicals of organic synthesis.

I recall that in one corn field, planting had been delayed — sure enough, a pattern of rye grass made its stand. Here the crop was planted too long after cultivation. By the time seeds went into the soil, weeds were on the way. I recall one alfalfa field that had been the victim of poor soil management for seven or eight years. The soil was waterlogged and distressed. And weeds of several types increased and multiplied.

It became standard procedure to recommend pH adjustment according to the gospel of Albrecht, and well digested compost. Compost contains its own nitrogen in perfectly available form. It often acts as a precursor of bacteria-fixing nitrogen in the field. Even then it was axiomatic that you never get blue-green algae with N, P, and K.

This business of management, or lack thereof, figured everywhere the Acres U.S.A. pencil and camera went. At one western dairy, it was practice to cut hay and treat it on the spot with an enzyme hormone complex, bio-cultured by Albion Laboratories out of Clearfield, Utah. In a matter of hours, the crop was put up as part of silage or hay bales. Before nightfall the same field got its shot of irrigation water. Weeds rarely got a toehold in such a well managed field, even though herbicides weren’t used.

Weeds seem to have a pecking order. Once the conditions that permit foxtail and fall panicum are erased, there will be other weeds, but none of them will be as difficult to control or as hazardous to crop production. They have names, both Latin and common. Lambsquarters is one. Pigweed is another. But now the message is different. Both lambsquarter and pigweed say soil conditions are good and fertility is excellent, and there is no reason to come unglued when they appear, for they are as Joe Cocannouer says in Weeds, Guardians of the Soil, a message that the crop will thrive and insects will stay away.

Cocklebur also indicates that the soil’s phosphate level is good. Lambsquarters, pigweed and cocklebur suggest a trio of superlatives, namely wholesome, highly productive, good quality soils. They are not hard to manage with clean tillage, and do not call for inputs of chemistry from the devil’s pantry.

In watching crops grow, other clues have surfaced over the years. There are relatives of grasses that reflect wet soils and wet conditions. Barnyard grass and nut sedge warrant mention.

On the other side of the equation, the same soil that produces each of these nemeses can produce ragweed, a dry weather phenomenon. This is particularly true when the crop is one of the small grains.

Often the soil tends to dry out as the crop matures. With soil moisture low, bacterial systems do not function too well because, of course, they require water. They do not function to release or convert potassium in a proper form. When the potassium supply from the soil is restricted for whatever reason, or held in a complex form, ragweed reveals itself inside the grain crop. With harvest, contamination in the grain bin becomes apparent.

Ragweed tells the farmer that he has poor quality and a wrong form of potassium during the dry part of the crop season. In the cornbelt, when there is too much rain after fall plowing, and in early spring when cold, cloudy weather holds on for a three-week period, then fall-tilled fields still open will generate a whole new crop of bitterweed or smartweed. These arrive under wet soil conditions and grow early in the season. They are related to poorly structured and poorly drained soils.

More important, these weeds shout out in understandable terms that something is wrong with the direction of decay of organic matter. Soil that is not in the proper equilibrium will put the decay process into the business of manufacturing alcohols and formaldehyde — in short, embalming fluids.

A good example is often the progenitor for morning glories and other rhizome crops that defy destruction. Picture cattle being fed out on the edge of a field. A lot of waste hay and straw piles up, cemented into place by urine and manure. Two or three years later this mixture is turned under, usually in an effort to return the area back to crop production. The problem is that Jimson weeds and buttonweeds, not crops, will grow. There is a reason for this. They are growing in soils with an excess of organic material that is not decaying properly. A hormone-enzyme process of a different bent takes over. It wakes up weed seeds and allows them to flourish.

The solution is not an overdose of herbicides, but manipulation of pH, distribution of the pileup of organic matter, which in any case must be mulched in more completely. When decay starts to go in the proper direction, Jimson weeds and buttonweeds simply stay dormant and no longer grow in that area.

The same principle applies to morning glories and field bindweeds. The last two weeds grow in sick soils, in eroded soils, and in each case they increase and multiply because they are started by an improper decay of organic material.

About Charles Walters

Charles Walters founded Acres U.S.A., and completed more than a dozen books as he edited Acres U.S.A., while co-authoring several others. A tireless traveler, Walters journeyed around the world to research sustainable agriculture, and his trip to China in 1976 inspired others to travel to this then-mysterious society. By the time of his death in 2009, Charles Walters could honestly say he changed the world for the better.

Meet the Vibrating Weeding Broom: DIY Weed Control Tool

By Takao Furuno

In 2016, after a long period of trial and error, I quite by chance tried out a “vibrating weeding broom” for weed control that uses a rake with thin, spring steel wires and was able to carry out continuous (down the row) early interplant weeding without damaging the crop.The weeding was successful using the vibrating weeding broom (VWB), and I named it hawking, after the Japanese-style broom called a hawki.

Takao Furuno with his homemade Interplant weeding broom.

Crops (rice, wheat and other cereal grains, soybeans, maize and vegetables) are often planted in rows. The space between the rows is known as inter-row space. The spaces in between the crop plants in a row are called interplant spaces (see Figure 1).

Inter-row weeding is known as intertillage weeding. Since there are no crops growing in this space, weeding can be carried out quickly by moving forward or backward continuously with a hoe or other hand tool, or a machine.

On the other hand, in the interplant spaces the weeds and the crops are close to one another, so it would seem to be difficult to eliminate only the weeds by moving forward continuously with a machine without harming the crop.

For nearly 40 years as an organic farmer I was convinced that mechanization of interplant space weeding cannot be easily done and continued to weed between the plants using my hands or a triangular hoe. There are probably many farmers around the world who think and do the same.

Handmade Tool for Weed Control

When I talk about the VWB, someone always asks, “Where can I buy it?” I made the VWB myself by modifying a store-bought rake (with thin spring steel wires).

You can buy many different kinds of rakes, but the ones I use have spring steel wires angled down at the end — this part is about 12 cm long (AB in Figure 2), and the main part of the wire (BC in Figure 2) is about 35 cm long.

I recommend making your own VWB to help you understand how it works. You will also be able to improve it by using your own ideas (technological self-sufficiency).

Cabbage hawking. Hawking with cabbages
is easy because they are transplanted.
Right: First hawking with Japanese daikon.

The rakes use stiff spring steel wires that radiate out in a fan-like manner. Looking at the shape of the broom, many people think that vegetables will be uprooted in addition to weeds. Widen the space between the steel wires on one of the rakes and try hawking an appropriately sized vegetable.

It is possible to use one rake, but the weeding effectiveness improves significantly if three or more are used in series. As shown in Figure 2, I use four rakes held together. As you can see in Figure 2, the wires jut out toward the left when seen from the handle, and some of the wires are cut off with wire clippers to leave only six on each rake.

The handles on each rake, except for one, are cut off at a length of around 60 cm. The distance between the tips of the wires (tines) on each rake in the series is about 12 cm (m in Figure 2). Using cardboard as packing material, secure the four handles firmly in place using duct (waterproof) tape.

Figure 1. Inter-row and interplant spaces.

The distance between the wires on each of the rakes is adjusted to about 6 cm. The rakes usually come with a metal tool for adjusting this distance (B in Figure 3). This adjustment is very important. If it is not just right, the vibration does not work correctly.

The final stage is to try hawking a plot of soil that has no weeds or grass. Look at the shape of the track to ensure that the wires are moving correctly and adjust them while looking to see how they interact together. You can also adjust the angles of the wires on each of the rakes so that the wire tips are all on the same plane (i.e. they all touch the ground at the same time). This may sound complicated, but it’s easy to do.

Mechanism of Interplant Weeding

Root Matters

In the paddy fields where I rotate crops, the crops germinate about two weeks after sowing. At about the same time, the sprouts of a great variety of early weeds, including shortawn foxtail (Alopecurus aequalis), green foxtail (or bristlegrass, a species of annual grass, Setaria viridis), Japanese barnyard millet (Echinochloa esculenta (A. Braun) H. Scholz (1992)), chickweed (or stitchwort, Stellaria sp.), shepherd’s purse (or shepherd’s pouch, Capsella bursa-pastoris), lambsquarters (Chenopodium album), buttercup (Ranunculus japonicus) and others show above the surface of the soil to form a green carpet over the whole paddy field if left undisturbed.

Weed (3) in Figure 3 is one that has just sprouted from a shallow point beneath the surface of the soil and has not yet sent out roots. Weed (4) is one that has just sprouted by sending up a mesocotyl from some distance below the surface of the soil and has almost no roots.

Although there are exceptions, almost all early-stage weeds have thin roots that spread out just below the surface of the soil or have almost no roots at all. In contrast, crop plants such as rice, cereal grains, soybeans, vegetables and so on, compared with weeds, have strong roots which spread firmly and penetrate down to a deeper level (around 3 cm). This early-stage dissimilarity is vitally important in hawking.

Movement of the Wires: Vertical Vibration

As you pull the VWB along the ground, as in A in Figure 3, the tip of the VWB wire pierces the soil under the roots of the weed at an acute angle, like a hoe, catching onto the roots and pulling them upward and pulling the whole weed out of the ground. It then drops the weed on the surface of the soil, where it withers and dies.

Figure 3. Difference in the roots of early-stage weeds and crops.
Weed (1) Roots spray out just below soil surface
Weed (2) Shoot out a mesocotyl and roots spray out just below soil surface
Weed (3) Has sprouted but not yet sent out roots
Weed (4) Has shot out a mesocotyl and sprouted but not yet sent out roots

By a combination of the wire’s own weight and the power used to pull the broom, the tip of the wire is always forced to pierce the soil at an acute angle, but as it pierces deeper it meets with the resistance of the soil and is pushed back but then returns to the original position due to the force of repulsion in the stiff spring steel wire. Thus the tip of the wire vibrates vertically, piercing the soil at almost the same depth (1 to 2 cm) as the broom moves forward.

Horizontal Vibration

What happens with weeds like Weeds (3) and (4) in Figure 3 that have not yet developed roots that the tip of the wire can catch onto immediately after sprouting? These will be weeded by the horizontal vibrating motion of the wires. Figure 2 shows the overall view of a VWB with four rakes in series. Grasping the handles R and S, if you pull the VWB over the crop plants, i.e. perform interplant weeding, each of the wires, spread out like a fan, pierce the ground at an acute angle, and due to the resistance of the soil and the springiness of the steel wire, oscillate (vibrate) horizontally violently and noisily, stirring up the soil as they go.

The result of this is that the Weeds (3) and (4) in Figure 3 that have not yet developed any significant roots will be moved around with the soil, and their roots (if any) and mesocotyl being severed will dry out, be buried, wither and die.

Figure 4. Difference between the VWB and
conventional spring steel wire weeding
machines.

The wires are made to jut out to the left of the overall VWB in order to make good use of this special property of the fan-like arrangement of the wires. At first, I carried out hawking with the rakes arranged symmetrically with respect to the backbone of the VWB. When I did that, the central wires located just under the backbone hardly showed any horizontal vibrations at all and weeds remained for a certain interval on both sides of the wires.

Structure of the Multi-Rake Broom

Why does the VWB use four rakes? Naturally, the smaller the distance between the wires, the more effective we would expect the weeding to be, but things are not that simple. This is because the crop plant’s leaves and stems become sandwiched between the wires, which will also pull along rice straw and clumps of soil, or push over, rip out or bury the crop plants.

In contrast, if the distance between the wires is too large, some weeds will remain in the soil after you have carried out the hawking. The multi-rake broom structure resolves this problem. As in Figure 2, there are four rakes in series, and the distance between the wires is set at 6 cm.

Since the early-growth vegetables are small, they easily pass through the 6 cm interval, and they are not pulled out by the roots. However, since the wires of each of the rakes are aligned so that they are offset from each other (i.e. are not following on from one to the next in a straight line), from the viewpoint of the weeds, which have shallow roots, this is the same as having a gap between the wires of 6 cm divided by 4=1.5 cm. Moreover, the horizontal vibrations of the wires further decrease this 1.5 cm gap, pulling out and pushing aside the weeds, providing satisfactory weeding.

Vibrating Weeding Broom At-A-Glance

The soil is pierced at an acute angle: The rakes from which the VWB derive pierce the soil at an obtuse angle, as seen in Figure 4. With the acute angle, the resistance of the soil is greater, and the spring steel wires catch onto the weeds, lifting them up out of the ground as the wires vibrate strongly both horizontally and vertically due to the properties of the spring steel wire. In contrast, the spring steel wire weeding machines produced by British and Japanese makers, as in Figure 4, have the tips of the spring steel wires make an obtuse angle with the ground surface, seemingly stroking the soil. This is perhaps a different way of thinking about the weeding mechanism. View hawking video at bit.ly/2uaZyas.

The VWB is a specialized interplant weeder: The VWB focuses on the interplant space to carry out aggressive interplant weeding.

Requires less labor and strength and is speedy: To perform interplant weeding of 100 meters of vegetables with a triangular hoe or by hand will take you two hours. If the conditions are right, carrying out hawking over 100 meters will take one minute. Check out the video clips!

Pocketbook-friendly appropriate technology: A rake will set you back 980 yen ($11) in the Japanese DIY store. This is appropriate and simple technology that is cheap and can be handmade by farmers. This is the kind of simple technology that many people all over the world have worked to produce throughout the long history of humanity.

Practical Hawking for Weed Control

The mechanism of hawking differs from all conventional weeding techniques and requires some further thinking and tweaking. The technique is still in the trial-and-error testing stage, but the following are a few key observations I’ve made.

Plowing

Plowing carried out before sowing or transplanting of the crop plants is done to break the soil up into fine particles so that the weeds do not survive. If quite large weeds are remaining at this stage, they cannot be dealt with by hawking. However, it is not necessary to break up all the soil in the ridges and furrows into fine particles. I break up the surface layer of the ridges to a depth of 1 to 2 cm.

Appropriate Crops

Grains such as rice directly sown into dry fields, wheat and other cereal grains, soybeans, maize and so on have large seeds, robust and flexible leaves and stems and sturdy roots and are therefore the easiest crops for use with hawking. Interplant weeding by hawking is also very easily done on potatoes and the yam eddoe (Colocasia esculenta (L.) Schott) at the early stage.

However, these crops are generally cultivated using land-extensive methods. For larger areas, it will be necessary to mechanize hawking. Since around 2007, I have been collaborating with the development division of the Fukuoka agricultural machinery maker Orec to develop a weeding machine for dry fields. Since February 2016, after much creative activity, we have started work on the mechanization of hawking.

We found that, among sown vegetables, hawking works well with daikon radish, white turnip, Japanese mustard spinach (Brassica rapa var. perviridis), spinach, edible chrysanthemum (Chrysanthemum coronarium), potherb mustard (Brassica rapa var. nipposinica), burdock and others. However, if the leaves and stems are pulled too much, branched roots occurred in burdock, and the white turnip became an oval shape. It is especially important when trying out hawking to experiment and find what works best for your farm.

Among the transplanted vegetables, hawking was found to work well with cabbage, lettuce, takana (Brassica juncea var. integrifolia), katsuona, onion, kujo leek, chives and others.

In general, as transplanted vegetables have firm roots that go deep into the soil, once they get settled into the soil hawking is a very suitable technique for weeding. In contrast, it was surprisingly difficult to use hawking with Chinese cabbage and carrots. I intend to take up the challenge with these crops again this year.

Timing

There’s no simple answer to the question, “What’s the right time to carry out hawking?” I look at the condition of the crops and weeds and make a judgment based on what I see. In general, a good time is when the crop plants have reached a certain size and the weeds are just beginning to sprout. In reality, however, the weeds sometimes sprout and grow before the crop plants do. In this case, I carry out inter-row hawking before interplant hawking. When the soil on both sides of the crop row is soft and loose it is easier to carry out interplant hawking. Once the weeds exceed 3 to 5 cm in height, the roots are generally quite strong and it becomes difficult to remove them by hawking.

Successive Strategy

Vibrating weeding broom with four broom
units in series.

In contrast to conventional weeding methods, weeding is not completed by carrying out hawking just once. During hawking a number of times the vibration of the wires makes the soil soft and loose, fewer weeds are seen and it becomes more difficult for them to grow.

By carrying out hawking intensively two or three times when the crop plants have reached a certain size eliminates weeds well. If the interval between hawking sessions is too long, the weeds will become larger and much more difficult to remove by hawking.

Soil condition

As a rule, hawking should be carried out when the soil is dry. The soil will then become soft and loose and the weeding effect will be better. With some types of soils, however, when the soil is very dry it will be too hard for the tines to penetrate in some places. In these cases, it is probably effective to carry out hawking after rain has fallen and the surface of the soil is softer.

Troubleshooting to Avoid Crop Damage

• Issue: The crop plants are still small and the roots are not yet well developed. Solution: Wait.

• Issue: The wire tips pierce too deeply. Solution: Adjust the angle of the wires and the weight of the VWB.

• Issue: The wire tips do not pierce the soil and pass over the leaves of the crop plants. Solution: Adjust the angle of the wires and/or lower the handle when pulling the VWB.

• Issue: The crop plants are injured just by contact with the wires (this mainly occurs in the morning with lettuce when the leaves are a little stiff after absorbing a lot of water). Solution: In the afternoon, when the temperature has risen and the leaves are wilting a little from the sun and wind, hawking can be carried out by increasing the interval between the wires and passing slowly down the row. It is also possible to fix some sponge rubber on the wires to prevent leaf damage.

• Issue: Lumps of soil and straw get caught between the wires, causing the crop plants to get pushed over. Solution: Increase the interval between the wires and carry out more careful plowing.

• Issue: The crop plants become covered in soil. Solution: The crop plants are too small; wait a while. Increase the interval between the wires and pass down the row more slowly.

See the vibrating weeding broom in action here and here.

This article was originally published in Japanese in Tsuchi to Kenko (Soil and Health – journal of the Japan Organic Agriculture Association), July 2017 (#475). pp. 16-22

This article appeared in the May 2018 issue of Acres U.S.A.

To contact Takao Furuno, email furuno@d4.dion. ne.jp (the author asks that readers please keep inquiries short and easy to understand for a non-native English speaker).

Weed Control: Mulching Questions Answered

By Anne Van Nest
From the May 2011 issue of Acres U.S.A. magazine

Weed control through mulching makes sense for many growers, but there are often questions about sourcing, safety and sustainability. May is a critical time for many gardeners to deal with existing or imminent weed issues before problems get totally out of control. Mulching is a key component of a multi-pronged approach to gaining the upper hand in the weed control battle.

Is Cypress Mulch Sustainable?

Shredded cypress is a popular mulching material for weed control because it is slow to decompose and the long strands lock together and don’t blow or float away easily. Attractive and natural looking, cypress mulch has many fans in the garden. The majestic swampy cypress forests across the Southeast, where most of the cypress mulch is harvested, are a true ecological sanctuary and face encroaching building development as more and more people flock to the Sunbelt. Gardeners are now beginning to look at the source of their mulch and question the sustainability of cypress mulch harvesting.

A group called Save Our Cypress is drawing attention to the harvesting practices of cypress for use as lumber or mulch. Their website says that “in the past cypress mulch used to be a by-product of lumber mills. This is no longer true. The mulch purchased today comes from widespread clear cutting of entire ecosystems.” The Save our Cypress website lists several alternatives to cypress mulch including leaves, pine straw, recycled yard waste, pine bark mulch and eucalyptus mulch.

Supporting the harvesting practices of the cypress mulch industry, the Mulch and Soil Council — a mulch certifying industry group — reports that in Louisiana,“cypress forests are growing six times faster than trees are being harvested with 400,000 new cypress trees planted each year and even more naturally regenerated.Cypress trees are not being cut in areas such as flooded swamps where they will not re-grow. Most harvested cypress is sold to sawmills. The by-products from these sawmills are sold to the mulch industry to deal with the disposal of their debris.” Using a waste by-product for mulch reduces the threat of this debris being a fire hazard or ending up in over-burdened landfills.

Whether you think that cypress mulch should be avoided because there are more sustainable alternatives or not, there are many alternatives to consider. But should colored mulches be your alternative to cypress mulch for weed control?

Are Mulch Colorants Safe?

Setting aside the fact of whether you think mulch colorants look natural or not, the aesthetically pleasing aspect should take a backseat to the health issue of whether the mulch colorants are safe for pets, plants, people and the environment. It’s a standard of good stockmanship. A little homework or a phone call before purchasing or contracting for your mulch delivery should be able to give you the answers you seek. Many of the bigger mulching companies, such as Mobile Mulch Systems in St. Paul, Minnesota, use iron oxide pigments in their mulch that come from natural sources. They say that these colorants have proven to be completely safe for the environment. Another large mulch company, Amerimulch, uses water-based formulations, rather than solvent-based colors, which they say produces a safer colored mulch product.

The Mulch and Soil Council have investigated the use of colorants in mulch products and found that the red colorants from iron oxide have been used for centuries and are currently used extensively for many other products such as facial cosmetics and paints that result in close, frequent human interaction. They found no specific concerns with the red color used to dye mulch.

They also investigated the black used in mulch coloring. They found that carbon black “is virtually pure elemental carbon and is used in many consumer and industrial products such as tires, belts, virtually all other rubber goods, video and audiotapes, nearly all electric motors as the brush contacts, insulators, and dry cell batteries. As a pigment, it is used as a toner for paper copiers and printers, inks for newspaper, and in most dark-colored paints and coatings. Given the wide manufacture of both pure carbon black and products containing carbon black, there is a wealth of information published on the human health aspects of this material. Occupational studies over 60 years do not show any increased health risk to workers exposed to carbon black compared to the general public.”

The Mulch and Soil Council did not find any evidence that any of the components of colorants were an environmental concern when used according to label directions and rates on mulch. Dyed mulch aside, some people are not concerned so much with the colorants used for mulch. Instead, people like David Beaulieu are concerned with what is used for the mulch. He says on the About.com Landscaping website, “The source of most dyed mulch is recycled wood. So far, so good. But the problem is that some of that recycled wood may be (chromated copper arsenate) CCA-treated wood, which, used as a mulch, can raise the arsenic level in your soil. Although the use of arsenic in making pressure-treated lumber was largely banned after 2002, who’s to say part of the source of the dyed mulch you’re buying isn’t old, leftover CCA-treated wood?” Beaulieu recommends looking for Mulch and Soil Council (MSC) certified mulch that is free of CCA-treated wood.

A good suggestion from a mulch industry worker at Amerimulch.com is to look at the type of company supplying the dyed mulch. The industry has two types of suppliers: those who are land clearing companies and take the logs to a lumberyard and grind up the smaller pieces into mulch; and those that are wood waste recycling companies that take used wood and grind up whatever they can get for mulch. The suggestion is that the land clearing companies will have products that are CCA-free and the wood recycling companies’ products have the chance that CCA-treated wood could have made it into their batches.

Is Cocoa Bean Mulch Toxic to Dogs and Cats?

The sweet smelling cocoa bean shell mulch that is popular in some parts of the country could be very hazardous to your pet. Chocolate can be toxic to your pets. The ASPCA, on its website, addresses reports that “dogs who consume enough cocoa bean shell mulch could potentially develop signs similar to that of chocolate poisoning, including vomiting and diarrhea.”

It is the residual quantities of theobromine found in chocolate that causes the trouble for dogs and cats. “We advise pet parents not to use cocoa mulch in areas where dogs can be exposed unobserved, particularly dogs who have indiscriminate eating habits,” says Dr. Steve Hansen, ASPCA Senior Vice President of Animal Health Services. He recommends shredded pine, cedar or hemlock bark as alternatives. The ASPCA website also mentions that no dogs have died from ingesting cocoa mulch and a large quantity is needed to make them sick.

On the About.com website, the Merck Veterinary Manual is referenced and approximate levels of theobromine in different types of chocolate are listed as: dry cocoa powder = 800 mg/oz, unsweetened (Baker’s) chocolate = 450 mg/oz, cocoa bean mulch = 225 mg/oz, milk chocolate, 44-64 mg/oz.

According to Dr. Rhea Morgan in The Handbook of Small Animal Practice, a toxic dose of theobromine is 100-150 mg/kg for dogs.

As an example, a 20-pound dog (9 kg) would have to eat 900-1,350 mg of theobromine, which would be 4-6 oz (.25-.4 lb) of cocoa bean mulch to receive a toxic dose.

Does Using Mulch Attract Termites and Ants to Buildings?

Donald Lewis from the Department of Entomology at the Iowa State University Extension admits that subterranean termites can be routinely found in wood chip mulch. He says that worker termites come to the soil surface to feed on wood and other cellulose materials and carry this back to share with other colony members. A moist environment such as that created under mulch is an inviting place for termites, and they will search it out. Tests done in Iowa with different types of mulches to see if one type favored termites found that mulch type had little effect and that surprisingly gravel mulches proved to be a magnet for termites.

One valuable pointer that Donald Lewis mentions is to keep mulch several inches from a house foundation, windowsills or house siding. Also watch wood chip mulch for signs of termite activity and call in a professional for an inspection and treatment estimate.

Are Newspapers Safe to use as Mulch for Weed Control?

In 1977 the U.S. Consumer Product Safety Commission banned the overall use of lead paint. This was followed by an EPA ban of lead in printing ink in 1985. Today’s newspaper inks contain mostly carbon black, varnish, polyethylene wax, china wood oil (tung oil), soybean oil and linseed oil. Ohio State University Extension, reporting on a study looking into the safety of using shredded newsprint bedding with black ink for livestock announced that “There is little threat of dermal absorption of ink or its ingredients once the ink is dry because the ink has achieved its stable state. The ingredients that were potentially absorbable become dry and are no longer able to be absorbed.” Charles Walters, founder of Acres U.S.A. would be the first to say that faulty logic would prevail if we believed in the assumption that newsprint being proclaimed safe for livestock bedding by Extension Agents also should be safe to use as mulch among vegetable plants — especially if non-black ink is used.

In 2005, the NOSB board approved in a formal recommendation to the National Organic Program that newspaper or other recycled paper, without glossy or colored inks (as well as the use of plastic mulch and covers other then PVC types) continue to be included on the National List of substances used for crop production.

Are Mulch Volcanoes Around Trees Harmful?

First, what are mulch volcanoes? Mulch volcanoes are the steep piles of excessive mulch banked up against a tree trunk. Piling mulch up like this is a very unhealthy practice and can lead to rodent, insect and disease problems and if excessive and long-term, could even kill the tree. Mulch should be kept away from tree trunks and not placed any higher than the root flare, (the flared out area at the base of the tree trunk) which should still be visible after the mulch is applied.

Gary Bachman at Mississippi State University recommends that gardeners contour the mulch layer to resemble a bowl and make sure the mulch does not touch the tree trunk. This way the bowl shape will collect rainwater or irrigation and direct it toward the tree roots, rather than having it run off of the steep-sided volcano shape. Let’s ban the practice of creating mulch volcanoes!

Flame Weeding: Turn up the Heat to Fight Weeds

By Francesca Camillo
From the May 2012 issue of Acres U.S.A. magazine

Flame weeding (also referred to as flaming) has been an apt option for organically ridding row crops and fields of uninvited weeds while also replenishing the soil with nutrients from the resulting carbon. Wedding the proficiency of flame with the compressed liquid power of propane has served many farmers and food producers well over the past century. According to the Northwest Coalition for Alternatives to Pesticide, the first agricultural flame weeder was patented in 1852.

Flame weeding is done by generating intense heat through a chosen device — whether it is a handheld torch or tractor-mounted — that sears the leaves of the weeds, which causes the cell sap to expand, thusly damaging the cell walls. “You’re watching for the color change, depending on the weed and its maturity,” said Charles House of Earth & Sky Solutions. Leaves wilt and dehydrate the plant, leaving the invaders no other option than to die, sometimes up to three days later.

“The key to successful flame weeding is the maturity of the plant you’re trying to eradicate. The smaller, the better,” he explains. The best time is when they’re immature and in the cotyledon stage.

Flame Weeding Background

Flaming gained popularity in the first third of the 20th century and continued through the 1960s until pesticides replaced industry attentions. Though its use waned over the following 20 years, flame weeding resurfaced and regained popularity in the early 1990s, and continues to be used today. So continues flame weeding’s renaissance.

One man whose agricultural history includes using and refining his flame weeding technique is Charles House. Approximately 30 years of experience in many sectors of green industry has endowed him with ample knowledge. As a purveyor of agricultural farm equipment and owner of Earth & Sky Solutions, based in White Hall, Virginia, he has been able to create a business model in which he can share the knowledge he gained from his years of experience.

“When I owned a landscape company, I got into using chemicals for a time because that’s what the market wanted. I got tired of it. And in fact, I refuse to use chemicals anymore.” His experiences have allowed him to contour his personal and professional philosophy and act as an educational and consultation resource for people who may not know much about flame weeding and its benefits, but are interested in learning. For House, flame weeding is possibly the most logical answer to eradicating weeds.

“With flame weeding you don’t have to use chemicals. There are so many benefits, [among which are that] you don’t have to worry about drip.”

Fueled by propane, flame weeding allows the user to not worry about spillage or drip, since it’s safely contained and is accessible on an as-needed basis. Says House, “When propane is under moderate pressure, about 200 psi, it remains liquid and burns anywhere from 1200 to 2000°F, averaging at about 1400°F.” This range is thoroughly sufficient to eliminate weeds in a garden or in row crops organically, quickly and easily.

Of course many, if not all of us, know better than to play with liquid propane, right? Another issue that may seem obvious would be to use it with a lot of ventilation — and since you’ll be flame weeding your yard or row crops outside, that shouldn’t be a problem. It’s always important to prevent electrostatic charges from building up when in a liquid state, outside of the cylinder. And, if you have an open container of liquid propane, don’t use any hand tools, or anything that sparks, within the vicinity. Always wear protective clothing. Some people even use face shields. If there’s a spill, propane will evaporate quickly.

“Many organic farmers opt for flame weeding, since there are no side effects or environmental ramifications.” Another positive aspect of flame weeding is that, as House explains, “You’re not cultivating the soil. When you cultivate soil, you’re digging up weed seeds that will [eventually] germinate — it’s like a no-till type method. You’re using the flame to disrupt the growth of the weeds.”

Flame Weeding Methods

There are three methods of flame weeding: spot-flaming, pre-emergent flaming and indiscriminately treating whole beds. The stale seedbed technique begins controlling weeds early in the season, especially in direct-seeded crops, according to Appropriate Technology Transfer for Rural Areas (ATTRA). When the seedbed is prepared, the soil is tilled and set/hilled into beds, which encourages weeds to germinate and make their way to the surface. In order to have a weed-free bed, farmers will flame the soil after tillage, but prior to planting to ensure the seed crops have precedence. Some farmers will even pre-irrigate to induce weed growth, and then sweep through with the flame to kill them all off. This technique can also be helpful when preparing to transplant, essentially giving the vegetable seeds a head start so that they can develop the canopy cover that will greatly reduce weeds’ ability to flourish. The earlier the weeds are taken care of, the better it is for the crops to maximize their yield.

The pre-emergence flaming technique eliminates the first round of weed seedlings just before the crop seedlings emerge, since the weeds often surface first. This ensures the crop will not be harmed and nicely compliments crops that are slow to germinate.

flame weeder on wheels — Flame weeders range in size, from handheld to tractor attachments for row crops.

House discussed post-emergence flaming, also known as “selective flaming,” a fair amount throughout our interview. This technique requires more finesse and control, since the crop plants have broken through the surface and are stretching their way toward the sunlight. Although it may seem counter-intuitive to brush your crops with over 1200°F of propane-fueled fire, time is of the essence, and hardy plants can stand it. Once the row crop is out of the cotyledon stage, it will be much more likely to withstand the heat.

There are myriad flaming techniques outside of these three. Some farmers opt to cross flame, parallel flame, middle flame, and there’s even water-shielded flaming. “Torque adjustment is key, as well as the maturity of the plant that you’re trying to protect, and ground speed,” House says.

Subtle movements and being mindful of velocity and tension can make for fast, efficient work. “Penetration of the flame is only a few centimeters into the soil, and when you flame, you leave organic matter in the soil,” House explains. This is essentially biochar.

Biochar

According to the CarbonZero Project, biochar is “created using a pyrolysis process,” which is the thermochemical decomposition of an organic element. In the case of flame weeding, the organic elements are the uninvited weeds that are trying to be eradicated. To further elaborate on a seemingly simple process, a “biomass is heated in a low oxygen environment, and once the pyrolysis reaction has begun, it is self-sustaining, and requires no outside energy input.” When a farmer flame weeds his or her row crop, this process is occurring with each sweep of the flame-tipped hose.

In many cases, when farmers use biochar on crops, it’s spread across the top layer of soil. Flame weeding omits the physical application of biochar, saving farmers time while adding nutrients to the soil that turns something invasive and uninvited, into a helpful, nourishing presence. A generous amount of research shows that it can increase crop yields. Biochar has high porosity and has been known to retain moisture and replenish organic carbon levels in the soil; further, it also prevents fertilizer runoff and leeching, which decreases the need for fertilizers, and ultimately decreases pollution of soil and surrounding areas.

Deciding on whether or not to flame weeds depends on the condition of the site, and exercising good, old-fashioned common sense is the best policy. It never hurts to dig into the soil to test the seedlings’ progress. Physically knowing where the plant is will always help you best gauge when and when not to flame. Asking oneself if the crop has grown too large so that the method of flaming has become prohibitive is a viable starting point. Essentially, can you get in there? If not, you may want to change the device, but if that’s cost-prohibitive, other options should be explored.

As with most things, flame weeding proficiency comes with repetition. The more you do it, the more you can refine your technique. A popular method is to use a sweeping motion, “away from your body, but it all depends on what type of unit you’re using,” House cautions. “With a hand torch, it’s typically a sweeping motion. Think about using an eraser — flame weeding is really a weed eraser.”

He suggests to “do some prep first and get combustible materials out of the way before flaming. Combustible material has a life span of its own.” That life span can be, and often is, short, but it can also be more protracted, so be careful. “Stay away from rayon,” he says facetiously, though with seriousness.

“Some people say they get better results when they flame when it’s still a bit wet,” House explains, since “water is a really good conductor of heat.”

On the whole, flame weeding may be one of the best options for ridding one’s space, whether a garden or a multiple-acre farm of weeds. As an organic process, its benefits are twofold: as it kills weeds and gives crops or other plants an opportunity to grow, it replenishes the soil of nutrients without any human effort. As a succession of natural processes, it’s both accessible and intuitive, making it a universal tool for farmers across scales.

For more information visit Earth & Sky Inc., Way Cool Tools or Flame Engineering,Inc.

This article was originally published in the May 2012 issue of Acres U.S.A.

Non-toxic Management Practices for Weeds

Charles Walters describes important farm management practices concerning soil health and the identification and non-toxic treatment of weeds.

By Charles Walters

For now, it seems appropriate to walk through farm management practices worthy of consideration. How they fit soils in any area and how they dovetail with crop systems projections becomes all important for the grower who wants to minimize the hazards of weeds so that he does not have to depend on the obscene presence of herbicides to control them.

Fall Tillage

Fall tillage has to be considered number one. It is the first thing a farmer should want to do, yet every fall when the crop is harvested, that bad weather always seems to arrive. Often the fall work does not get done. The farmer is too busy harvesting and he can’t get in there and do the tillage.

Moreover, most crops are harvested late because schoolbook technology has given us degenerated soils. We do not convert and use fertilizers, nitrogen and other fertility factors locked up in the soil to properly grow field-ripened crops.

Proper fertility management would see to it that harvest can take place a month earlier and thus permit time for that fall work. That is when compaction could be best removed, when trash could be mulched in. That is also the time when pH modifiers could be applied. That is when lime and other nutrients could be used to influence the quality and character of the soil’s pH, all in time to meld into the soil during fall and over winter.

It is this procedure that would make the soil come alive in spring and get the growing season underway so that crops can germinate a week or ten days earlier.

Fall tillage is an important key to weed management. It is certainly one way to diminish the chances for foxtail and grass type weeds. If fall tillage is used to put soil systems into ridges, those ridges will drain faster in spring. They will warm up a week to ten days earlier. They will have germinating capacity restored earlier and permit planting earlier so that the economic crop can get a head start on weeds.

Once the soil is conditioned, it won’t be necessary to turn the soil so much in spring. Obviously, every time the soil is turned, more weed seeds already in the soil are exposed to sunlight and warmth and other influences that wake them out of dormancy. Soil bedded in the fall, with pH modified so that the structure does not permit crusting when spring rains arrive, will permit rain to soak in faster, bringing air behind it. Such a soil will warm faster and therefore determine the hormone process that will take place. Good water and air entry into the soil will not likely set the stage for foxtail (image below), nut sedge, watergrass and other debilitating influences on the crop.

Foxtail can be avoided with practical weed management — Anhydrous ammonia is almost an insurance policy for its proliferation. Foxtail grows in organic matter soil where there is a surplus of humic acid. Although pH adjustment has been front burner stuff so far, the topic has to surface in any discussion of the foxtail weed problem.

When the cash crop is germinated under these conditions, that is when your little pigweeds and lambsquarters, your broadleaf weeds — which require a good quality available phosphate — hand off their message. They say the phosphate conversion is good and the fertility release system is more than adequate to grow a high-yielding crop.

Such broadleafs are easy to manage. When they germinate and achieve growth of an inch or less, and you tickle the soil before you insert the seed, they are easily killed off. As a consequence, the hormone process gains the upper hand for four to six weeks, a time frame that permits the crops to grow big enough to be cultivated.

Organic Materials in the Soil

Needless to say, the bio-grower has to depend on proper decay of organic materials in the soil. Root residue and crop stover are always present, and these have a direct bearing on how prolific weeds might grow. This means farmers, one and all, must learn how to manage decay of organic matter better.

As we incorporate it into the soil, preside over proper decay conditions by pH management and regulate the water either present or absent, we achieve plenty of air and good humid conditions that will allow organic material to decay properly and in the right direction to provide the steady supply of carbon dioxide necessary for a higher yield.

While adjustments are being made in the soil — soils are sometimes out of equilibrium for years — it is unrealistic to expect the situation will be corrected in a single season or a single month. We can speed the process with the application of properly composted manures. The point here is that there is a difference between quality of various composts, just as there is a difference between predigested manures and manures sheet composted in the soil itself.

Readers of Acres U.S.A. in general, and those who have enjoyed the short book, Pottenger’s Cats, will recall how that great scientist planted dwarf beans in beach sand at Monrovia, California, as part of an experiment. Cats had been raised on that beach sand. Some had been fed evaporated milk, others raw meat, still others meat that had been cooked to achieve near total enzyme-destroying potential and some had been fed on raw milk. Cats fed evaporated milk, cooked meat — dung going into the beach sand — produced a dilapidated, depressed crop of beans. Cats fed whole milk — their dung also going into the beach sand, produced a prolific and extended crop, the dwarf bean variety growing to the top of a six-foot-high cage. The quality of manures used in composting have a direct bearing on the performance of that compost.

Experience has taught all those who wish to see that the kind of compost Fletcher Sims of Canyon, Texas, introduces into the soil has many desirable fungal systems of bacteria and molds. These have the capacity to attack rhizome roots of quackgrass, Johnsongrass, and those type of roots so far under the top of the soil they cannot be reached with physical tools. Compost tells us that we have to set in motion an environment with antagonistic fungi that will attack the rhizomes when they are in a dormant phase as the season begins to close.

In late August and early September, the length of the day shortens. Everything starts to go into fall dormancy. If at that time we can apply a wholesome, properly composted material to the soil and have it working for thirty days before the soil freezes and becomes inactive, a lot of weed cleanup work takes place at that time. Compost will simply digest most of the dormant weed seeds, and in two or three years of this approach seeds are literally vacuumed up, like soil particles on the family room carpet.

The key is timing. When weeds go into dormancy, they are subject to decay. They can be turned into fresh humus, rather than a charge of gunpowder ready to explode. Quackgrass in particular responds to the compost treatment. With calcium-adjusted pH, compost will attack quackgrass roots and rot them out in one season. The same principle operates with deep-rooted rhizomes, Johnsongrass and thistles.

Quackgrass signals soil decay systems are poor — *Quackgrass, sometimes called couchgrass. Agropyron repens is shown here (A); its spikelets (B); the ligule (C); and florets (D). Decay systems are at fault when this weed appears.*

The simplest way to start a biological weed control program, then, is to adjust the pH. This affects the intake of water and makes it possible to manage water.

In the cornbelt, where rain often comes at the wrong time and where droughts frustrate the best of intentions, this management of water and its capillary return is front burner stuff. pH management directly relates to so many desirable things, there is justification for referring the reader to the several volumes of The Albrecht Papers for background insight.

Soil Management

Each weed has a direct bearing on the track record of the farm. Each reflects back to what the farmer has done correctly or incorrectly over the years. Too often — in this age of super mechanization — we have large fields with soft spots and hard textured soils. The farmer moves across one then over the next area because he feels impelled to farm big fields with big machinery. All the low soil is too wet, and so a pass through sets the stage for wild oats or foxtail in corn, or fall panicum.

Some soils get the wrong treatment simply because they, not the weeds, are in the wrong place. It may be that the eco-farmer will have to redesign the shape of his fields, or plant in strips so that similar types of soils can be planted at the same time, with due regard being given to the need for soils to dry out and warm up and drain properly. It might be better to wait a couple of weeks. A little delay is better than wet soil work which leaves no chance at all for a crop.

As far as weeds as related to insects, the great Professor Phil Callahan has given us a roadmap that cannot be ignored. He called it Tuning In To Nature, and in it he related how the energy in the infrared that is given off by a plant is the signal for insect invasion.

It stands to reason that a plant that is subclinically ill will give off a different wavelength than the one with balanced hormone and enzyme systems. That these signals match up with the signals of lower phylum plants is more than speculation.

While writing An Acres U.S.A. Primer, I often made field observations that supported Callahan. It became obvious that when farmers did certain things in the soil, the crop could endure the presence of insects because they seemed incapable of doing much damage. I didn’t know how the mechanism worked, at least not before the release of Tuning In To Nature.

Weeds are going to tell about the nutritional supply, and they therefore rate as a worthy laboratory for making judgments about the soil’s nutritional system. They can often reveal the nutrients that must be added to the foliage of the growing crop to react with the negative effects of stress. After all, all growing seasons have variable degrees of timing and stress. It is not only necessary to arrive with nutritional support in time, it is mandatory.

The many mansions in the house of weeds all have family histories. They tell more about gene splicing and DNA manipulation than all the journals of genetic engineering put together. And if we pay attention during class, weeds are our greatest teachers. To learn our lessons, we have only to get into the business of watching weeds grow.

Source: Weeds—Control Without Poison

What Weeds Tell Us About Soil

Weeds are not inherently bad by nature. The informed farmer will know what the presence of various types of weeds means – from compacted to overly wet soil, and more. The late eco-farming expert and Acres U.S.A. founder Charles Walters explains different types of weeds, and the soil conditions and state of soil health that their presence signals.

By Charles Walters

Andre Voisin, the great French farmer and scientist who wrote Soil, Grass and Cancer and Grass Productivity, once declared that most of what he knew came not from the university, but from observing his cows at grass. And so it is with much of what we know about weeds.

Walking the fields with the late C.J. Fenzau in areas as separate as Indiana, Iowa and Idaho, I was able to take note of what weeds were trying to tell us during the early days of the Acres U.S.A. publication. Admittedly, this knowledge has been fleshed out since then. And recent findings build on, rather than tear down, those field observations.

Weeds are an index of what is wrong — and sometimes what is right — with the soil, or at least with the fertility program. In every field on every farm, there are different soil types, and each has a potential for producing certain weeds, depending on how a farmer works the soil. Fall tillage, spring tillage, tillage early or late, if it takes place when the soil is dry or wet, all these things determine the kinds of weeds that will grow that season.

Weeds and Water

There are soil conditions that almost always have restricted amounts of water, and consequently they do not require and cannot grow weeds that thrive when there is plenty of water.

In high rainfall areas of the United States, where irrigation is paper thin and where farmers depend on rainfall for their crop moisture, broadleaf weeds — lambsquarters, pigweed (image below), Jimson weed, buttonweed, and so on — often proliferate.

Weeds and soil – pigweed likes moisture — Green Amaranth, a.k.a., palmer amaranth, careless weed, spleen amaranth, red amaranth, rough pigweed, smooth pigweed, pigweed.

These special conditions appeared classic when C.J. Fenzau and I walked several farms near What Cheer, Iowa, one summer. Where the soil structure was poor and farmers worked the soil under wet conditions, they usually built compaction or set up sedimentary levels in the soil from filtration of silt. This set the stage for a lot of grassy weeds. And in only moments, it seemed, the corn farmer is forced to endure the vicious effects of foxtail and fall panicum.

The soil’s potential might remain. For the season, this pattern of weeds indicates a degenerated soil structure. That’s the signal foxtail and fall panicum send out loud and clear — that there is an imbalanced pH condition in the soil, that tight soil is holding water in excess and refuses to permit it to dry out.

To control the foxtail, it now becomes necessary to change the structure of the soil, and this means tillage, fertility management — not least, pH management, efficient use of water, development of capillary capacity and aeration of the soil. This much accomplished, there is no need for atrazine or other chemicals of organic synthesis.

I recall one alfalfa field that had been the victim of poor soil management for seven or eight years. The soil was waterlogged and distressed. And weeds of several types increased and multiplied. It became standard procedure to recommend pH adjustment according to the gospel of Albrecht, and well digested compost. Compost contains its own nitrogen in perfectly available form. It often acts as a precursor of bacteria-fixing nitrogen in the field. Even then it was axiomatic that you never get blue-green algae with N, P, and K.

This business of management, or lack thereof, figured everywhere the Acres U.S.A. pencil and camera went. At one western dairy, it was practice to cut hay and treat it on the spot with an enzyme hormone complex, bio-cultured by Albion Laboratories out of Clearfield, Utah. In a matter of hours, the crop was put up as part of silage or hay bales. Before nightfall the same field got its shot of irrigation water. Weeds rarely got a toehold in such a well managed field, even though herbicides weren’t used.

The Hierarchy of Weeds

Cocklebur (image below) also indicates that the soil’s phosphate level is good. Lambsquarters, pigweed and cocklebur suggest a trio of superlatives, namely wholesome, highly productive, good quality soils. They are not hard to manage with clean tillage, and do not call for inputs of chemistry from the devil’s pantry.

In watching crops grow, other clues have surfaced over the years. There are relatives of grasses that reflect wet soils and wet conditions. Barnyard grass and nut sedge warrant mention. On the other side of the equation, the same soil that produces each of these nemesis can produce ragweed (image below), a dry weather phenomenon. This is particularly true when the crop is one of the small grains. Often the soil tends to dry out as the crop matures. With soil moisture low, bacterial systems do not function too well because, of course, they require water. They do not function to release or convert potassium in a proper form. When the potassium supply from the soil is restricted for whatever reason, or held in a complex form, ragweed reveals itself inside the grain crop. With harvest, contamination in the grain bin becomes apparent.

Ragweed (image directly above) tells the farmer that he has poor quality and a wrong form of potassium during the dry part of the crop season. In the cornbelt, when there is too much rain after fall plowing, and in early spring when cold, cloudy weather holds on for a three-week period, then fall-tilled fields still open will generate a whole new crop of bitterweed or smartweed. These arrive under wet soil conditions and grow early in the season. They are related to poorly structured and poorly drained soils. More important, these weeds shout out in understandable terms that something is wrong with the direction of decay of organic matter. Soil that is not in the proper equilibrium will put the decay process into the business of manufacturing alcohols and formaldehyde — in short, embalming fluids.

A good example is often the progenitor for morning glories and other rhizome crops that defy destruction. Picture cattle being fed out on the edge of a field. A lot of waste hay and straw piles up, cemented into place by urine and manure. Two or three years later this mixture is turned under, usually in an effort to return the area back to crop production. The problem is that Jimson weeds and buttonweeds, not crops, will grow. There is a reason for this. They are growing in soils with an excess of organic material that is not decaying properly. A hormone-enzyme process of a different bent takes over. It wakes up weed seeds and allows them to flourish.

The solution is not an overdose of herbicides, but manipulation of pH, distribution of the pileup of organic matter, which in any case must be mulched in more completely. When decay starts to go in the proper direction, Jimson weeds and buttonweeds simply stay dormant and no longer grow in that area. The same principle applies to morning glories and field bindweeds. The last two weeds grow in sick soils, in eroded soils, and in each case they increase and multiply because they are started by an improper decay of organic material.

Sometimes the decay process produces formaldehyde, and at certain stages there is methane, ethane and butane production. These byproducts of decay stimulate the birth of the hormone systems that penetrate ubiquitous weed seeds and tell them to come alive and establish the growth kingdom for that season.

Generally, these processes do not occur throughout the entire field. Almost always, it is a spot here, an eroded hill there, always areas in which something has gone wrong in the past. These are dangerous weeds, and they are very destructive. They climb up plants and drag them down. They short-circuit yields and confer harvest problems on the best of machinery, and often account for farm accidents. Many farmers are maimed for life because they have tried to unplug harvesting equipment, the missing hand or arm a legacy of improper soil management.

Weed Patterns and Crop Performance

There are many factors that have a bearing on weed patterns and crop performance. They’re all interrelated. The ideal is to have pH control, good loamy soil texture, enough decaying organic matter to set the things in motion for better crop and changing weed patterns. These things diminish the frictions of stress and myriads of things that happen.

Every year conditions are different and there has to be different timing. Variables invite changes. There is no way you can machine the process. You can have watergrass come into a waterlogged soil. The next year you waterlog it early and let it dry, and in the early part of the season you get smartweed, a variable of stress reaction.

Different conditions invite a different echelon of life to come in. There is a variable in man — his operating style. I recall a farmer who had everything going perfect. But this year instead of taking a spiketooth rake and dragging it over the corn as it was emerging, the worker assigned the task. By the time he got around to it, the weeds were 3 inches tall. Corn was coming up puny. It was enough to make one shudder. Physical management mistakes can undo everything.

Smartweed can be an indicator of nutritional stress.

These few observations from the field already suggest that the topic of weeds is a very complex subject. The best weed manual in the world can only hint at solutions to the many problems related to weeds. Unfortunately, those who have taken the weed situation by the nape of the neck and the seat of the pants over the past fifty years have done little more than shake out poisons, not results. Here our objective is to establish a positive viewpoint so that we can analyze what weeds are and accept the Creator’s plan while we appreciate the romance of the tribe.

A Brief Glance at Weed Varieties

There are many mansions in the house of weeds. For example, there are swamp weeds, the cattails and the rushes. There are desert weeds. There are weeds that grow in sand and weeds that grow in silt, and there are weeds that grow in gumbo so tight it resembles modeling clay. Foxtails grow in gumbo, but they also grow in sand when such soils are out of balance and the electrical tension on soil particles is so tight that even sand can build clods and restrict air in the soil enough to set free the hormone process that wakes up foxtail seeds.

There are subsoil weeds. There are weeds that grow in acid conditions and — in the West — there are weeds that like alkaline conditions. Up in Wisconsin and Minnesota there is a weed called “devil’s paint brush” by the locals. This one joins the daisy in having a love affair with sour soils.

Almost always, such soils have an excess of iron and flush out a lot of trace minerals and rock minerals that support the hormone processes that give permission to live for these weed species. It is impossible to grow a high yielding crop when such conditions prevail. It is possible to grow red clover, mammoth clover instead of alfalfa because alfalfa simply won’t have much of a chance as a quality foliage crop.

There are sour soils, neutral soils, alkaline soils and salty soils, and there are weeds that identify with all of these conditions. There are weeds that relate to wet soils and weeds that embrace hot conditions and others that like colder conditions. The degree of sunshine and the length of day and night figure in nature’s equation.

There are weeds that get a head start on the farmer and those that emerge only after the farmer has done his job. All of these weeds have a biography and all seem to share their prophecy with those who look and actually see.

Take rotten weeds, weeds that actually exhibit rotting conditions in the soil. Take stinky weeds and fungal weeds. All reflect the sour, sick, dead excess toxic level of soil components.

There are even herbicide indicator weeds, weeds that grow too well after an accumulation of a certain level of herbicides, usually over several years. Such weeds build up a negative effect on the desirable biological things that have to happen if crop production is to be successful. These weeds tell the United States Department of Agriculture that a measure of madness is afloat when spokesmen make their annual pronouncement that without herbicides and chemicals fifty million U.S. citizens would starve.

There is a damning finality to the evidence that has piled up since Acres U.S.A. began publication twenty-five years ago, because this evidence proves that soils subjected to herbicide use year after year have now achieved a negative depressing effect and gifted degeneration to the soil system, with resultant shortfalls in crop yields. Once such soils are cleansed of herbicide residues, yields can be increased as much as 50 to 75% without the addition of more fertilizer inputs. Moreover, once these soil conditions are corrected, there is a chance to manage the weeds without the use of toxic genetic chemicals.

Every weed, generally within twenty-four to forty-eight hours after germination, has the ability to emit auxins. These are growth factors that come off the seed via rootlets and penetrate out into the soil, sometimes as much as a half-inch from the seed itself. That auxin tells every other species in the immediate neighborhood to stay asleep.

There are hundreds and thousands of seeds in every square foot of soil, and yet only so many germinate and grow each year. They seem to know better than to crowd each other out. Another year, other seeds get their chance. There are enough seed deposits in most soils to last fifty, one hundred, even five hundred years, and some seeds live that long. As long as the chemistry and biology and environmental conditions are there, certain species will wait. The dust storms did not annihilate the tumbleweed seeds or terminate the prickly pear, and all the laws passed to proscribe noxious weeds or prevent seed transport from farm to farm, county to county or state to state are merely so many monuments to the stupidity of man.

Crop Planting and Non-Toxic Weed Management

There is a lesson in all this. As the weed seed germinates, it emits those growth factors. Astute farmers can use weeds to their benefit.

In the spring, when preparing the rootbed, watch the warming and the curing and the ripening and the germinating capacity of the soil system being established. Always, certain weed seeds will start to germinate. The day that you go out and scratch the soil and see germinated weeds with roots about an inch long, that is the time to change the concentration of carbon dioxide and oxygen in the rootbed, and place the desired crop seed.

Within the first twenty-four hours that little weed seed has done its job. It has given off auxins enough to dormatize every other weed seed next to it. It is nature’s form of population control. It just allows certain weed seeds to come alive and stake out a proper domain, meaning space to ensure enough light, air, drainage, ventilation and carbon dioxide to prosper and produce new seed, the Creator’s purpose for a plant.

At the stage of its growth when it germinates, that little weed seed is very susceptible to dying. It can be killed easily simply by taking light tillage equipment through the soil to change the oxygen content. Cation balance, pH, the phosphate level, moisture, air — all determine how long an auxin system will endure in the seedbed. Soils that are completely dead and have no biological capacity, no balance, no equilibrium, soils abused to death with hard chemistry or imbalanced inputs of salt fertilizers, make it possible for the weed crop to hit the ground running, so to speak.

Auxins from weeds can endure in the soil for as long as six to eight weeks. Unfortunately, in most soils managed under the precepts of mainline agriculture, crop auxins can endure only three or four days. That is why partial and imbalanced fertilization usually becomes a sales ticket for insurance spraying, a benchmark for the chemical amateur.

Wild Mustard — Wild mustard is usually related to a field planted to small grains and the development of slime molds. The weed grows best in areas stressed due to poor drainage and poor structure. Control comes down to applying good compost or nitrogen to get the decay process moving properly. Above, an artist’s conception of pinnatifida variety (A); the seedling (B); a flower (C); siliques, an elongated fruit divided by a partition between the two carpels in two sections (D); and seeds (E).

Thus the equilibrium established in the soil determines how long growth factors can endure and exercise a dormatizing effect on a crop of weeds. If good biological management gives the crop seed time enough to send out its hormones and say, I command power over this domain for this generation, weeds cease to be the grower’s boogeyman and coffee klatch excuse for bad farming.

No one need accept my word for this. As Rudolf Steiner often said, “Experiment, experiment!’’ Almost every corn grower finds that certain rows were missed or that there are gaps in certain rows. The instant impulse is to replant, sometimes one seed at a time. But it never comes to anything. The new and later plants lack vigor and seem deprived of the potential they ought to have. The reason is simple. The other rows out there have already taken command over that soil domain and do everything they can to shut down the come-lately arrivals. They have sent their hormones out into the soil, and injected a negative effect for the replants to field.

That is why it is necessary when planting any seed crop to control the depth of planting and the spacing of the seed, so that they all come up on equal footing.

Any seed that germinates one or two or four days later than the seed placed next to it never has the potential for producing a high-yielding, field-ripened harvest. Weeds have the most serious effect on crop production during the first week or ten days of their life. That is why a small weed, one only a half inch above the surface of the soil, has such negative effect on the yield and quality of the crop.

C.J. Fenzau, my consultant for An Acres U.S.A. Primer, was so adamant on this point he sometimes repeated it several times in the same conversation. “We must control weeds in the early stages,’’ he would say. “Once the crop is this tall [indicating a foot or more] and a few weeds arrive underneath, they aren’t going to have much of a chance to do a lot of damage.’’

The Bottom Line on Weeds

Across more counties than most people see in a lifetime, this has been the lesson I learned “watching crops grow.’’ You can live with these weeds because they have less effect on yield and quality than when the corn crop is emerging from the soil with weeds arriving at the same time. In theory some of the pre-emergent herbicides set up this condition, but their legacy of damage is worse than the problem they presume to solve.

The bottom line is simply that good soil structure, good soil drainage and good aeration can control biological activity in the soil. In turn, the farmer can increase the nutrient supply and grow a high-yield crop even if a few weeds are supported underneath. But a sick soil with inadequate nutrient release and conversion will have a depressing effect on the yield potential. This allows the weeds to have a more negative effect simply because there are not enough nutrients to feed both the desired crop and the weeds. It also allows weeds to impose water limitations.

Weeds can set up severe competition for water, plant nutrients, air and light. If a crop is dominating and restricting the amount of light, then the light that filters through to the weeds underneath is subdued. Thus the weed is not able to grow as fast as its programmed genetic potential might otherwise allow. Instead of having a fat stemmed plant with a lot of root capacity, it is restricted because it failed to get enough light, and thus becomes a weak, thin-stemmed plant, one with smaller heads.

Any farm reporter who travels from one end of the country to the next can observe how weeds reflect reasonable variables such as altitude, sea level conditions, the amount of light and the angle at which the sun is exposed to that part of the earth. All these things have a bearing on establishing the character and the form and the potential of various weeds. You see some weeds that are short and blocky and thick-stemmed with great leaves, and others that are tall with thin stems and small leaves. These are all reflections of growing conditions. That is why weeds are an indicator of the limitations that exist. Farmers who learn how to read them find that this knowledge confers an ability to make better management decisions on how to live with weeds and still grow a good crop.

Source: Weeds—Control Without Poison