Using Cottonseed Fertilizer

Fall 2007
Far Better Options Exist

by Alex Owre

High-nitrogen content (6-2-2) cottonseed meal is an organic fertilizer that lowers the pH of soil, poses little danger of burning plants, and provides nitrogen, phosphorus and potassium as well as many minor plant food elements. It is cheap and readily available.

In some states, however, cottonseed meal is not allowed in a certified organic operation. It also does not appear as a recommended soil amendment in MOFGA’s Fact Sheet Number 11, “Natural Sources of Plant Nutrients.” (See

Eric Sideman, Ph.D., MOFGA’s organic crop specialist and author of the fact sheet, says the omission is due to two restrictions on using cottonseed meal in the USDA’s National Organic Program (NOP) standards. The first restriction requires that cottonseed meal be pesticide free, which, says Sideman, though possible, is difficult to demonstrate. Though cotton is a heavily sprayed crop, pesticide-free meal is available on the market.

Is it organic?

The International Certification Standard set by the Organic Crop Improvement Association places cottonseed meal in the Restricted category. This means that it may contain substantial pesticide residues and recommending its use only if documented to be residue-free. Otherwise, you MUST compost cottonseed meal before use to break down toxic residues. We recognize Cotton gin trash, which contains seed hulls, as a potentially more contaminated meal than the seed meal, because many residues are in the hull.

The cotton industry’s stance

The conventional U.S. cotton industry says that “if there is any trace of residue [on cottonseed meal] it is minuscule and far below levels to harm anyone  … Essentially the only crop protection products used on cotton are used before boll opening. Only harvest aid products are applied after boll opening and these products are contact leaf defoliants, not systemic. In addition, cotton fiber and cottonseed hulls would cover and protect the cottonseed meal from any crop protection product exposure.” In other words, cottonseed fertilizer is basically non-harmful to their standards.

Note that this is not always true for genetically engineered cotton, which expresses the gene for the Bacillus thuringiensis bacterial toxin in all plant parts. Thus, the second NOP restriction cited by Sideman: that cottonseed be free of genetically engineered material. This means it’s hard to trace the organic roots of cottonseed fertilizer unless the meal is organic.


Other than that, Sideman suggests cottonseed meal the same as he does for soybean meal. He notes, however, that soybeans, by comparison, pose little pesticide risk. Soy is not genetically engineered to contain a toxin in all of its cells, as cotton is. Soy is made to resist the herbicide Roundup by altering a gene in the plant, not by adding genes. MOFGA allows soybean meal from any source as a soil amendment.

Local alternatives

Rather than rely on an “imported” product to provide fertility to the farm or garden, MOFGA recommends farm-generated fertility or, at least, recycling fertility within a community. This makes economic as well as environmental sense.  A 4-pound bag of cottonseed meal costs just a little under $6. This mean you’d pay $6 for 0.24 pounds of nitrogen, or about $25 per pound of nitrogen. For comparison, alfalfa meal costs about $46 per pound of N; blood meal, $12;  soybean meal, $17.  These prices are based on small quantities, such as 5-pound bags.

Four pounds of hairy vetch seed (for a nitrogen-fixing green manure crop), on the other hand, will cost about $13 and can fix over 100 pounds of N per acre – for a cost of 13 cents per pounds of N. Growing your own nitrogen also adds lots of organic matter to the soil as well; protects the soil from erosion; helps keep existing nutrients from leaching; has less environmental impact than buying N from any off-farm source; and supports a diverse ecology in the garden.

Likewise, compost, leaves and grass clippings can supply all of the fertility you need in a garden and may be free – and collecting them can even save you from paying for a membership at a gym.

Please note: All material inputs used by certified organic producers are subject to a material review process to verify that they comply with the National Organic Program.

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