ORGANIC HERBICIDES

What works, what doesn’t, and what to do if you can’t spray.

The guy who invents a safe alternative to Roundup will earn millions!  Right now, there is a distressing lack of alternatives to glyphosate = Roundup.  Below is a short summation of available organic vegicides and alternative weed controls.  Choose the best formula or method for your farm.  Experiment until you obtain the degree of weed control desired.

HERBICIDE SCIENCE:     All organic herbicides work by desiccation = leaves dry out = plant death is caused by water loss.  Thus, organic herbicides perform reasonably well on ANNUAL broadleaf weeds and grasses, especially young plants less than 30 days old or 6 inches high.  Desiccant kill rates on young annuals or perennials normally range from  80% to 100%.  Mature perennial weeds (with long tap roots) and perennial grasses (with growing points below soil surface) are rarely killed by desiccant herbicides because these are contact chemicals only — the herbicide is NOT translocated to roots or other underground parts of the plant.  Spraying a desiccant herbicide will knock back perennial weeds (by burning down exposed foliage) but will not kill established plants.  Repeated applications are necessary to control perennial weeds; this is rarely economic so herbicide use must be integrated with other cultural practices to obtain desired level of weed control.  This often means rethinking how to grow and harvest crops.

COMMON LYE:     The cheapest burn-down herbicide is old fashioned lye; either sodium hydroxide (NaOH) or potassium hydroxide (KOH) works equally well.  Powdered sodium lye (for example, Red Devil Lye) is a special order industrial chemical that requires a signed application statement (because sodium lye is used to make illegal drugs).  You can make your own potassium lye at home simply by leaching wood ashes with water.  If a fresh egg floats in the solution, the lye is strong enough to kill plants (or make soap).

Potassium Lye Formula by Weight:     Prepare a 45% to 50% concentration by weight of water = 0.45 to 0.50 expressed as a decimal.  Note:  1 U.S. gallon of water weighs 8.34 pounds = 3.78 kilograms.  0.45 x 8.34 pounds per gallon of water = 3.753 = 3 3/4 pounds of wood ashes per gallon.  Sift wood ash through window screening before weighing.  Mix ash and water the night before use then strain most carefully before application.

Potassium Lye Formula by Volume:     Combine 2 parts finely sifted wood ashes with 3 parts water by volume.  Mix ashes and water then let stand overnight before use.  Decant and filter wood ash lye through paper coffee filters to avoid clogging lines and spray nozzles with grit.

All herbicides are more effective if a spreading-sticking agent is mixed with the solution.  To increase weed kill rates, combine lye with 2% commercial surfactant (surface active agent) by weight or volume.  The admix helps lye solution cover and grip foliage.  If commercial surfactant is not available, substitute an equal portion of common liquid dishwashing detergent.  Addition of 2% “Polysorbate-20” (a powerful emulsifier)  makes herbicide mixtures even more deadly by stripping away protective wax coatings on plant cell walls.

>>>  Concentrated lye solution can have a pH near 14 = it’s extremely caustic = highly basic = will change soil pH if used continuously or in high volumes.  Lye herbicide is NOT recommended for use around acid-loving plants like potatoes, raspberries, cranberries, blueberries, strawberries, azaleas, laurels, rhododendrons, pine trees or other conifers (plants with needle or scale-like leaves that bear seeds in cones).  Check soil pH regularly; it may not be necessary to apply agricultural lime to fields where lye herbicide is used frequently.

>>>  Where agricultural lime is too costly, spraying sodium or potassium lye solution is a cheap way to adjust soil pH.  For example:  To bring highly acid soils into production, spray lye then plant beans.

>>>  Substitute wood ashes where agricultural limestone is unavailable or expensive.  Swap 2 parts wood ashes by weight or volume for every part of powdered limestone.  Sift wood ash through window screening before use.  Crush charcoal screenings to pass 1/4 inch hardware cloth sieve then compost with an equal or greater volume of fresh manure before applying to garden or field.

MALEIC HYDRAZIDE is a chemical growth regulator commonly used to keep potatoes from sprouting in storage, and tobacco plants from suckering.  Maleic hydrazide is NOT an herbicide in the conventional sense of the word (although it does kill plants if used in high concentration).  Use maleic hydrazide to SLOW weed growth; sprayed weeds are stunted rather than killed.  Weeds are knocked back just enough to give crop plants a competitive advantage.  Translation:  If weeds are dwarfed then there is no need to kill them.

Never use the word “herbicide” when talking or writing to the Government about maleic hydrazide.  The official viewpoint is that maleic hydrazide is a plant growth regulator, NOT an herbicide.  Use the word “herbicide” and you may end up having to submit a ton of regulatory paperwork!

Maleic Hydrazide Formula by Volume:     Commercial maleic hydrazide is sold as a 30.3% concentrated solution by volume containing 2.25 pounds of chemical in 1 gallon of water (26.97841% concentration by weight).  Apply 1 to 1.33 gallons of chemical solution in 30 gallons of water per acre to control sprouting in potatoes.  This manufacturer recommended concentration gives you a place to start.  [2.25 pounds chemical per gallon of commercial concentrate / 220.2 pounds of water (30 gallons) in spray tank] x 100 = 0.89928% concentration by weight.  Adjust vegicide concentration until desired level of weed control is obtained.

Maleic Hydrazide Formula by Weight:     To stunt both annual and perennial broadleaf weeds and grasses, apply 0.6% pure maleic hydrazide by weight = six tenths of one percent = 0.6 / 100 = 0.006 expressed as a decimal.  For example:  0.006 x 1,000 grams per liter of water = 6 grams of maleic hydrazide per liter or approximately 0.21 scale ounce per quart of water (6 grams / 28.35 grams per ounce = 0.2116402 scale ounce = 0.21 scale ounce or about 1/5th scale ounce of maleic hydrazide per quart of water).  This concentration will control (don’t say kill)  even multiflora rose and other invasive shrubs and trees.  Maleic hydrazide is fast becoming a favorite weed control chemical because it is safe to handle, cheap, and effective.

AMMONIUM NONANOATE is a synthetic chemical, a detergent-like surfactant that kills weeds by dissolving the wax coating on cell walls.  Damaged cells leak water = weeds die of dehydration.  Think of ammonium nonanoate as a strong soap solution; wear rubber gloves and protective goggles to keep chemical off skin and away from eyes.  Spray herbicide at night to avoid harming most beneficial insects.

Soaps, detergents, and other surface active agents = surfactants kill insects by clogging their breathing tubes.  Soap-sprayed insects die of suffocation.  Thus, it is best to spray ammonium nonanoate and other herbicidal soaps at night to avoid killing as many beneficial insects as possible.

Ammonium Nonanoate Formula by Weight:     Ammonium nonanoate is sold as a 40% concentrated solution by weight.  Mix not more than 6% by weight of commercial concentrated solution in 1 gallon of water = 2.4% by weight of ammonium nonanoate in 1 gallon of water.  1 U.S. gallon of water weighs 8.34 pounds = 3.78 kilograms.  6% = 6 / 100 = 0.06 expressed as a decimal.  0.06 herbicide concentrate x 8.34 pounds per gallon of water = 0.5004 pounds of herbicide concentrate x 16 ounces per pound = 8.0064 = 8 scale ounces of commercial concentrate in 1 gallon of water.  (This is approximately equal to 8 fluid ounces or 1/2 cup of ammonium nonanoate concentrate in 1 gallon of water).

Note:  This chemical is not currently approved for use on organic farms in the United States.  Ammonium nonanoate is a type of industrial strength soap.

SODIUM LAURYL SULFATE (SLS) is a synthetic detergent commonly found in shampoo, toothpaste, and household cleaning products.  Sodium lauryl sulfate is a contact herbicide that works by stripping the wax coating from cell walls = leaves lose water then plants die of dehydration.  As with any strong soap, wear rubber gloves (to prevent skin from drying out) and safety goggles (to keep detergent out of eyes).

Sodium Lauryl Sulfate Formula by Weight:     Mix 5% to 20% dry chemical by weight in pure water.  1 U.S. gallon of water weighs 8.34 pounds = 3.78 kilograms.  5% = 5 / 100 = 0.05 expressed as a decimal.  0.05 chemical concentration x 8.34 pounds per gallon of water = 0.417 pounds of SLS x 16 ounces per pound = 6.672 = 6 2/3 scale ounces of sodium lauryl sulfate per gallon of water (minimum concentration).  20% = 20 / 100 = 0.20 expressed as a decimal.  0.20 chemical concentration x 8.34 pounds per gallon of water = 1.668 pounds of SLS x 16 ounces per pound = 26.688 scale ounces = 1 pound 10 2/3 scale ounces of sodium lauryl sulfate per gallon of water (maximum concentration).

Sodium Lauryl Sulfate Formula by Volume:     For commercial concentrated solutions, mix 20% concentrate by volume with water.  1 U.S. gallon = 128 fluid ounces = 4 quarts = 8 pints = 16 cups = 256 Tablespoons = 768 teaspoons.  20% = 20 / 100 = 0.20 expressed as a decimal.  0.20 SLS concentrate x 768 teaspoons = 153.6 teaspoons = 51.2 Tablespoons = 3.2 cups = 1 1/2 pints + 3 Tablespoons + 2/3 teaspoon = about 3 1/4 cups herbicide concentrate in 1 gallon of water.  Another way to figure this is:  128 fluid ounces per gallon x 0.20 herbicide concentration = 25.6 fluid ounces of herbicide concentrate needed  / 8 fluid ounces per cup = 3.2 cups = about 3 1/4 cups of SLS concentrate per gallon of water.

SLS Application Rate per Acre:     Apply 2.5 gallons to 7.5 gallons of diluted herbicide per thousand square feet of farm or garden = 109 gallons to 327 gallons per acre.  Note:  Herbicidal soaps are much more effective when powerful emulsifiers and surfactants are added to the mix.

>>>  There are many different kinds of herbicidal soap.  All work the same way and should be diluted to the same concentration:  5% to 20% dry chemical by water weight, or 20% liquid concentrate by volume.  Adjust concentration and application rate as needed to kill target species.  Weeds with hairy or waxy leaves are harder to kill than less protected plants.

D-LIMONENE:     Citrus rinds contain volatile essential oils (orange oil, lemon oil, grapefruit oil, et cetera).  The largest chemical component of all citrus oils is d-limonene, a fragrant chemical and powerful surface active agent = surfactant that quickly dissolves fats, oils, and waxes.  D-limonene is a common ingredient in most natural home cleaning products.  D-limonene is also used to wash greasy automobile parts and as a safe replacement for mineral spirits (petroleum turpentine).  Use d-limonene just like any other strong detergent (ammonium nonanoate or sodium lauryl sulfate, for example).  All herbicidal soaps work by dissolving the waxy coating on plant cell walls.  Damaged leaf cells leak water then plants die of dehydration.

Pure D-Limonene Formula:     Mix 55% d-limonene by weight in water.  Mix 50% orange oil (or other citrus oil), clove oil, cinnamon oil, or lemongrass oil by weight in water.  Essential oil concentration can be decreased to 30% by weight if Polysorbate-20 (emulsifier) and spreading / sticking agent (surfactant) are added to the herbicide solution.

D-Limonene Formula with Emulsifier & Surfactant:     Combine 30% limonene + 10% emulsifier (Polysorbate-20) + 10% commercial surfactant (wetting agent) + 50% pure water = 100% total by weight or volume.  Use baking soda to adjust solution pH to 5 or above.  Apply up to 100 gallons (approximately 400 liters) of diluted herbicide per acre (about 0.40 hectare).

D-limonene can also be used in small quantities as a surfactant (spreading / sticking agent) in other herbicide or insecticide formulations.  Add one-eighth percent to one-quarter percent = 0.125% to 0.25% = 0.00125 to 0.0025 expressed as a decimal = 1 to 2 pints per 100 gallons or approximately 2.5 milliliters per liter of water.

D-limonene makes an economic herbicide provided you live near an orange juice processing plant.  Prices rise as distance from citrus groves increases.

ACETIC ACID = VINEGAR:     For commercial farms concentrated vinegar = 10% to 20% acetic acid is required.  For household gardens, common white table vinegar (5% acetic acid) will suffice.  Strong acids (concentrated vinegar) and strong bases (sodium or potassium lye) both kill weeds by rupturing cell walls = leaves leak water till plants die of thirst.

Vinegar Herbicide Formula by Weight for Farming:     Combine 20% acetic acid (liquid) + 5% citric acid (powder) + 2% commercial surfactant (spreading / sticking agent) + 73% pure water = 100 total parts by weight.  Note:  To save freight costs, order glacial acetic acid = pure, undiluted acetic acid in 1 gallon glass bottles.  Mix 1 gallon of glacial acetic acid with 9 gallons of water to make 10 gallons of concentrated vinegar (10% acetic acid) solution.  Mix 1 gallon of glacial acetic acid with 4 gallons of water to make 5 gallons of concentrated vinegar (20% acetic acid) solution.

Vinegar Herbicide Formula by Volume for Gardening:     Combine 5 cups of common white vinegar (5% acetic acid) + 1 cup of bottled lemon juice (3% to 8% citric acid) + 4 Tablespoons of dish washing detergent (to help herbicide stick to leaves) = 6 1/4 total cups by volume.

For best results, spray on a warm, sunny day when weed leaves are dry.  Apply herbicide solution generously so that leaves are thoroughly wet.

Caution!  Concentrated vinegar is a hazardous chemical, a strong acid that will burn skin and eyes.  Wear rubber gloves and safety goggles.  Do not breathe concentrated vinegar vapors.  Work outdoors with the wind at your back = blowing away from you.  Wash skin or eyes with pure, distilled water if necessary.

CHELATED IRON:     FeHEDTA (Iron-Hydroxy-Ethylene-Diamine-Triacetic-Acid) in high concentrations (26.5% by weight) will kill broadleaf weeds in turf grasses.  This herbicide works well but is most costly = far too expensive for agricultural use.

SUNFLOWER SEED HULLS:     Some plants produce natural herbicides.  Sunflower seed shells can be used as mulch to retard weed growth.  Apply 1 to 2 inches of sunflower seed hulls around ornamental or edible plants.  Note:  Herbicidal effect may inhibit growth of flowers and crops!  Perform small plot trials before spreading large amounts of sunflower hulls.

BLACK WALNUT HULLS & WOOD CHIPS:     Black walnuts produce natural herbicides that kill some plants but not others.  For example:  Tomatoes are severely stunted or killed by walnut herbicide.  Test ornamental or crop plants first before spreading mulch of black walnut hulls or black walnut wood chips.

SMOTHER CROPS:     Plants that grow faster than weeds and cast dense shade make ideal smother crops.  Multiple smother crops (planted in sequence) are often used to clear especially weedy fields or to eradicate hard-to-kill perennial weeds with deep tap roots.  For best results, do not plow fields after growing smother crops; tillage stimulates weed germination.  Broadcast small grains or turnips over standing vegetation then immediately mow or roll to cover and protect crop seed.   Alternatively, mow or roll smother crop then set seeds or transplants through surface mulch using no-till equipment.  If smother crop is tilled into the ground (as a green manure) immediately broadcast clover or other legume seed to blanket field as a living mulch.  Fields must be covered with useful plants at all times or weeds will regain foothold.  Popular smother crops include Buckwheat (Fagopyrum esculentum) and Sudangrass (Sorghum sudanense)  in temperate climates, and Sunn Hemp (Crotalaria juncea) in tropical and semi-tropical zones.

Buckwheat Smother Crop:     Fagopyrum esculentum grows 0.75 to 1.25 inches per day reaching a mature height of 50 inches (3 tons of dry matter per acre) in 6 to 8 weeks.  Blooming starts around 32 days and seeds mature in 10 to 12 weeks.  Mow, crimp, or rototill buckwheat when plants are in full bloom, about 60 days after planting.  Do not let plants mature and drop seeds or buckwheat will become a weed in the following crop.  Seed 32 to 40 pounds per acre for small seeded varieties; 50 to 72 pounds per acre for large seeded varieties.  Ideal plant population is 700,000 plants per acre = 16 seeds per square foot.  Test weights vary from 44 pounds (large seeds) to 52 pounds (small seeds) per bushel.  Approximate seed weight varies from 29 to 37 grams (1.02 to 1.30 scale ounces) per 1,000 seeds = 12,200 (large seeds) to 15,600 (small seeds) per pound.

Sudangrass Smother Crop:      Sorghum sudanense grows fast and produces natural herbicides.  Translation:  Weeds are overwhelmed.  Sudan grass grows 1/2 to 2 inches daily if soil is warm and moist.  For best results sow when soil temperatures reach 65 degrees Fahrenheit ~ 18 degrees Centigrade and irrigate with 1 to 2 inches of water weekly.  Broadcast 30 to 50 pounds, drill 35 pounds, or precision seed 13.5 pounds of pure, live seed per acre.  Average seed weight ~ 42,300 seeds per pound.  Plant seeds 1/2 to 1 1/2 inches deep in rows 7 to 14 inches apart.  Under ideal conditions Sudan grass can reach 8 to 9 feet mature height in 8 to 10 weeks.  If temperature and moisture are unfavorable, Sudan grass may take 80 to 100 days to mature.  If desired, Sudan grass may be mowed about 55 days after seeding when plants are 20 to 30 inches tall.  Leave 8 inches of stubble to help grass regrow quickly.  In temperate climates Sudan grass may be cut 2 or 3 times yearly.  6 to 8 cuttings are possible in tropical and sub-tropical areas if soil is fertile and water plentiful.  For each cutting expect 2 to 3 tons of green mulch per acre at 70% to 75% moisture content.  Expect 10 to 12 tons of green chop per acre each year under average conditions.  Under ideal conditions annual production may reach 16 to 24 tons (fresh weight) ~ 4,000 to 6,000 pounds dry weight per acre.

Sudan grass has an enormous fibrous root system that can penetrate 6 to 8 feet into the subsoil.  This huge mass of organic matter restores life and productivity to “tired soils” and “sick fields”.  Sudan grass is one of the best cover crops for weed control and soil improvement.

Sunn Hemp Smother Crop:     Crotalaria juncea is a fast growing nitrogen fixing legume.  In temperate regions with 90 or more days of warm weather, Sunn Hemp grows 1 to 1 1/4 inches per day, reaching 6 feet high and flowering approximately 60 to 70 days from seeding.  In tropical climates some varieties of Sunn Hemp grow over 20 feet tall.  Broadcast 20 to 50 pounds or drill 15 to 40 pounds of pure, live seed per acre in 6 to 36 inch rows.  For precision seeders, use a 60-cell small sugar beet plate and plant 9 pounds per acre in 15 inch rows, or 5 pounds per acre in 30 inch rows.  (Remember to inoculate seed with nitrogen fixing cowpea rhizobia).  Sow seeds 1/2 to 1 inch deep.  Average seed weight = 18,000 to 35,000 seeds per kilogram ~ 15,000 to 33,000 seeds per pound.  Average test weight = 60 pounds per bushel.  Sunn Hemp is amazingly productive when planted in moist, fertile soils.  Expect 8 to 18 tons of green mulch (4 to 9 tons dry weight) per acre at 50% moisture content 10 to 12 weeks after seeding.  Under average conditions Sunn Hemp yields 6.25 to 7 tons of green chop in 60 days = weeds are buried under a great mass of stems and leaves.

There are many aggressive, rapid-growth plants suitable for smothering weeds.  Forage Radish (Raphaus sativus variety longipinnatus) and Forage Maize (Zea mays) are two additional examples.  Choose species and varieties best adapted to local soil and climate.

COMMON CEREAL RYE:     Grain rye (Secale cereale) produces natural herbicides.  The best way to employ this herbicidal effect is to grow a 5 to 6 foot high cover crop of rye and then cut it down with a sickle-bar mower (or use a roller-crimper) when the grass starts to flower or no later than the soft dough stage of seed development.  Leave cut rye straw where it falls.  Set pumpkins or other transplants through the rye mulch.  Alternatively, use a no-till seeder with a fluted coulter to plant through the mulch.  If desired, Dutch white clover (Trifolium repens) can be broadcast over the field the same day crops are transplanted.  Clover seedlings fill any gaps in the mulch providing 90% or better weed control under average field conditions.

You can run a 25-acre vegetable farm with nothing more than a common lawn mower and a hand-cranked cyclone seeder.  Broadcast lawn clover everywhere then transplant into the living mulch.  I can’t think of an easier way to operate a truck farm or market garden.

DUTCH WHITE CLOVER:     Trifolium repens is NOT herbicidal but it does make a good living mulch that can provide effective weed control in transplanted crops and winter grains.  Dutch white clover only grows 6 to 8 inches tall so it makes an ideal living mulch for any crop that grows a foot or more high.  For best results, transplant crops directly into standing Dutch white clover.  If desired, clover can be mowed first to give transplants a little more time to get established.  Sow clover at the same time that you plant winter wheat, barley, oats, and rye.  If convenient, Dutch white clover can be broadcast over established crops when they are young (6 to 8 inches tall) or later in the season (a few weeks before harvest).  Note:  If Dutch clover seed is not available substitute Crimson Clover (Trifolium incarnatum), Sub Clover (Trifolium subterraneum), or a low-growing variety of Medium Red Clover (Trifolium pratense).  A good stand of clover will blot out most competing plants providing 90% or better weed-free fields.

OVERLAPPING ROTATIONS:     Sometimes called “interseeding”, this technique uses the competitive ability of crop plants to suppress weeds.  The idea is to top seed the following crop several weeks before the previous crop is harvested.  This gives crop seeds time to germinate and become established.  When the overstory nurse crop is harvested, the understory crop already has at least 2 weeks head start over competing plants.  In nature, possession is 9 tenths of the law; the first population established will predominate.  By overlapping rotations, weeds never get a toehold.

Successful weed control requires careful timing, zero tillage, pelleted seed, and Dutch white clover (Trifolium repens) living mulch.  Always overseed at least 2 weeks before harvest so seeds have time to germinate ahead of any weeds.  Never disturb the soil for any reason; any tillage will encourage weed growth.  Always use pelleted seed; coated seeds have better germination and seedling survival.  Always use Dutch white clover to check weed growth; clover replaces herbicides and mechanical cultivation.  One last important detail:  Return all crop residues to the field and scatter randomly to form a thin, open mulch; a light blanket of straw or leaves is necessary to protect seedlings and feed the soil.

Rice-Winter Grain & Clover Rotation:     This is the basis of Masanobu Fukuoka’s “Do Nothing Farming” system.  [See:  The One-Straw Revolution, Rodale Press, 1978].  (1)  In fall, sow pelleted winter barley or winter rye seed with Dutch white clover.  (2)  A few weeks before winter grain harvest, broadcast pelleted rice seed over standing winter cereal.  (3)  Immediately after harvesting winter grain, scatter straw randomly over field to protect germinating rice seedlings.  (4)  A few weeks before rice harvest, top seed pelleted clover and winter rye or winter barley over standing rice.  (5)  Immediately after rice harvest, scatter rice straw randomly across field to protect germinating winter grain seedlings.  (6)  Repeat rotation indefinitely; the system works with any kind of summer and winter grain.  Choose crops to fit growing season length.  Note:  Continuous cereal rotations with understory clover companion crops place severe competitive pressures on native weed species.  Provided ground is not tilled, fields remain 95% weed free without herbicides or any other weed control methods.

Hogs make great rototillers provided they do not have rings in their snouts.  Ringed hogs cannot root.

Clover-Wheat-Turnips Rotation:     15th century Dutch farmers combined free-range pig ranching with no-till agronomy to make a low-cost sustainable agriculture system called the Clover-Wheat-Turnips Rotation:  (1)  Enclose a field of Dutch white clover.  (2)  Turn pigs loose in fenced pasture.  Pigs will uproot clover eliminating need for plowing and harrowing.  (3)  Broadcast wheat seed onto pig tilled earth.  (4)  Drive sheep back and forth across field; sheep will stomp wheat seeds into ground.  (5)  When wheat starts to head out, overseed grain with turnips.  (6)  A few weeks before turnip harvest broadcast clover seed over field.  Clover protects and fertilizes soil until cycle repeats in spring.  This rotation reliably yields 40 bushels of wheat (2,400 pounds) per acre = 2,694 kilograms per hectare under European weather conditions without irrigation, diesel fuel, synthetic fertilizer, herbicides, insecticides, or fungicides.

Overlapping crop rotations are remarkably stable — farmers have been using legume-grain-root crop rotations for 700 years.  Many other rotations are possible, with or without livestock or machinery.  Choose cash crops most suited to your local soil and climate.  Use cover crops or forage crops to fill any gaps in the planting season.  Soil must be covered with growing plants at all times = 365 days yearly.  As long as continuous vegetation is maintained fields will remain 95% weed free and crop yields sustained indefinitely.

MULCH-IN-PLACE:     It is impractical to mulch large fields by hand because the volumes required are too large.  The solution is to grow a mulch crop then kill it by mowing or crimping.  Seeds or transplants are then set through the surface mulch using no-till equipment specifically designed to work in high-residue “trashy” fields.  Alternatively, harvest the mulch crop with a silage chopper then apply with a mulch spreader; this technique is ideal for orchards, vineyards, nurseries, and berry plantations where labor costs are high.

The best mulch crops are quick growing grasses that yield high-tonnages per acre.  Grasses are preferred because straw decomposes slowly and forms a nearly impenetrable mat that blocks light and prevents weed emergence.  Fields need at least 4 to 5 tons = 8,000 to 10,000 pounds of straw mulch to obtain 90% weed control.  A 5 to 6 foot stand of grain rye (Secale cereale) produces 4 to 5 tons of long straw which forms a thick, weed-blocking blanket over the soil.  Forage maize (Zea mays) is even better:  It grows 12 to 15 feet high and produces 18 tons = 36,000 pounds of mulch in only 70 days from seeding to harvest.  100 to 120 day forage maize yields up to 30 tons = 60,000 pounds of mulch per acre.  30 tons of corn stalks per acre will obliterate any weed problem for 2 seasons or longer.  Top seed maize mulch with a low growing clover and fields will remain at least 95% weed free.

ZERO INPUT AGRICULTURE:     There are many terms for this technique (No-Kill Cropping, Natural Farming, Do Nothing Agriculture, Zero Budget Natural Agriculture, Minimum Effort Agronomy, Minimal Energy Agriculture, Zero Petroleum Agriculture, et alia).  The idea is to plant seeds into standing vegetation without tillage, herbicides, fertilizers, irrigation, or any other input.  Crops (usually small grains like wheat, oats, barley, and rye) can be sown directly into pastures, hay fields, range lands, or shortly before a crop is harvested (or immediately after a crop is harvested).  The keys to success are timing and seeding method.  The best time to plant is when grains would naturally reseed themselves (usually in the dry or dormant season).  The best way to plant is to disturb the soil as little as possible.  (The more soil is tilled = broken, the more weeds will germinate).  The best methods are to broadcast seed into standing vegetation (pelleted seeds greatly increase seedling survival) or to plant in shallow slits made by a no-till seeder.  Other than planting and harvest, no attention is paid to the crop.  In years with good rainfall, yields are typically 60% to 70% of conventionally grown crops.  In dry years crops are often not worth harvesting for grain (but do produce substantial quantities of forage or surface mulch to protect fields and increase soil organic matter).

Zero input agriculture is the best way to grow small grains where the climate is dry or soils are poor.  The method yields a surprisingly high return on investment because there is little financial risk (only the cost of seeding in a bad year, or the costs of seeding and harvest in a good year).  Because input costs are minimal, profit margins are high.  Thus, zero input agriculture can produce more income than conventional grain farming.

“No-Kill Cropping” is the wave of the future, a convergence of old-school mechanical agronomy with new-school biological agriculture.  The synthesis of these disciplines creates a new way of thinking about farming, an agro-ecological approach where problems are solved by nature rather than by petrochemicals.  Here, the idea is to grow crops and weeds together in mutual symbiosis, rather than spending vast sums to eradicate all competing plant life.

The first time I proposed planting weeds as cover crops, half my audience walked out of the conference room (I think they all worked for Monsanto).

WEEDS AS COVER CROPS:     Weeds make excellent ground covers well worth the cost of seed, fertilizer and irrigation.  Most fields already have sufficient weed populations.  Where land is barren or scraped down to subsoil, broadcast grain elevator screenings liberally.  Elevator screenings are cheap (often free) and contain many weed seeds.

As I write this paper (Monday 1 June 2015) it is almost time to transplant tomatoes in Butler County, Pennsylvania (40.8607 degrees North Latitude, 79.8947 degrees West Longitude).  My fields are a green sea of weeds.  Pigweed (Amaranthus blitum), Lambs Quarters (Chenopodium album), and Common Thistle (Cirsium vulgare) are already 2 to 3 feet high, a respectable nurse crop measuring about 2.5 tons of dry matter per acre.

After lunch I will mow or roll strips through the weeds, overseed each planting strip with Dutch White Clover (Trifolium repens), set 8-inch tall determinate tomato transplants every 4 feet, then run drip irrigation hose down the rows.  Most of the field remains covered by weeds which I leave undisturbed.  I will walk the field once or twice before harvest to rescue the odd tomato plant that gets too crowded by weeds.  A pair of pruning shears quickly dispatches offending vegetation.  The crop gets no other attention until destructive harvest which yields 8 pounds of Number 1 marketable fruit per plant at $0.60 per pound wholesale price for “spray-less tomatoes” (21,000 pounds = 10.5 tons per acre = $12,600 gross income per acre).  That is good money for very little labor and minimal investment (no plowing, staking, fertilizer, herbicides, pesticides, or fungicides).

Lawnmower Farming:     Find the weediest field possible = vigorous growth 5 to 6 feet tall.  Mow widely spaced strips through the weeds.  If possible, run irrigation tape down the rows.  Set transplants then mulch 12 inches deep with cut weeds — this is a form of cold composting known as sheet composting.  Green weeds contain twice the nutrients of fresh dairy cow manure.  Chopped vegetation rots quickly releasing nutrients to feed crops.  Leave remaining weeds standing to provide food and shelter for beneficial insects.  Lawnmower farming does not use land efficiently but it does grow crops cheaply = without tillage, herbicides, fertilizer, or pesticides.

Mow-And-Blow:     On large farms and plantations forage choppers replace common lawnmowers.  Modify delivery chute to deposit chopped vegetation into convenient windrows.  Set transplants and drip irrigation hose down the windrows.  Use mow-and-blow with any kind of vegetation:  Weeds, forage grasses, mulch crops, and mixed species cover crops all do well.  For best results choose plants that produce large yields of biomass = stems and leaves per acre.  If possible, irrigate and fertilize fields to increase mulch yields.

It pays to feed and water weeds.  Weeds use and recycle nutrients efficiently so a little fertilizer creates rampant growth = more biomass for mulch and soil improvement.  For best results apply dilute fertilizer in irrigation water.

>>>     The trick to using weeds as cover crops is to manage them just like any other conventional mulch crop or green manure.  Kill the weed crop by mowing, crimping, or spraying then seed or transplant through the mulch with no-till equipment.  Think of weeds as a mixed cover crop that costs nothing to seed!

>>>     Set aside an acre or two and experiment growing crops in weeds.  The first thing you will discover is that pests do not like weedy fields.  Crops grown in weeds rarely need sprayed.  Fertilizer costs can also be reduced or eliminated because weeds efficiently capture and recycle nutrients.  Water costs also decrease because weeds protect crops from drying winds.

>>>     The only disadvantage to farming weeds is that your neighbors will think you are crazy.  Count your profits and let the naysayers believe as they wish.

Martian Thinking:  “See what the Earthlings are doing, turn 180 degrees in the opposite direction, then work back to what makes sense”.

MARTIAN AGRICULTURE = WEEDS ARE PROFITABLE!     99% of farmers think that weeds are bad.  Eric thinks differently.  I encourage weeds to grow in my fields.  For example:  Why use herbicides in a small grain crop?  Herbicides cost money to apply (and even more money is lost because the crop cannot be sold as “natural” or “organic”).  Modern seed cleaners easily separate weed seeds from crop grains.  Weed seed meal makes ideal organic fertilizer.  (For highest profits sell weed seed meal in 40 pound bags to city gardeners).  Wild oats can be separated from weed seeds and processed into high nutritional value cereal (50% protein rolled oats).  Growing weeds in my grain means that I don’t have to apply insecticides (so I save even more money).  Weeds provide pollen and nectar for bees and other beneficial insects.  Weeds also support primary and alternate hosts for predatory and parasitical insects.  (You need to maintain small populations of “bad” bugs in order to sustain healthy populations of “good” bugs).  Having lots of weeds around helps balance farm ecology (which saves even more money on pest control in other cash crops).  And don’t forget that weeds have extensive root systems that break up plow pans  (compacted soil layers) and increase soil organic matter.  The way Eric looks at this is:  What I lose in grain yield (to weed competition) I gain in lower input costs and higher-margin specialty products.  Even in bad years, Eric always makes more money than his neighbors.  Why?  Because Eric is not looking to win a blue ribbon for maximum yield at the County Fair.  Eric measures success at the bottom line.  He who has more money in his bank account wins!

RELATED PUBLICATIONS:     Trash Farming, No-Till Hungarian Stock Squash, Planting Maize with Living Mulches, Living Mulches for Weed Control, and Crops Among the Weeds.

WOULD YOU LIKE TO KNOW MORE?     Contact the Author directly if you have any questions or need additional information.

Please visit:     http://www.agriculturesolutions.wordpress.com  — or —  http://www.worldagriculturesolutions.wordpress.com  — or —  send your questions to:  Agriculture Solutions, 413 Cedar Drive, Moon Township, Pennsylvania 15108, United States of America  — or —  send an e-mail to:  Eric Koperek = worldagriculturesolutions@gmail.com

ABOUT THE AUTHOR:     Mr. Koperek is a plant breeder who farms in Pennsylvania during summer and Florida during winter.  (Growing 2 generations each year speeds development of new crop varieties).

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