Cottonseed Meal Fertilizer Pros and Cons

We all know cotton is a valuable material worldwide. But its byproducts, like cottonseed meal, have value too!

With more and more people growing their own food, cottonseed meal is increasing in use. As an organic fertilizer option, it’s a slow-release pick. It provides more organic matter to your garden soil, too. And with over 14 million pounds of it produced every year, it’s constantly renewable!

Let’s cover the many uses of cottonseed meal. We’ll talk about how it’s made, the pros and cons, and how to use it properly.

What Is Cottonseed Meal?

When cotton is grown, it produces bolls. These bolls are filled with fine, soft material that grows over the seeds. If left in place, that soft cotton acts as a seed-dispersal method.

As we use that fiber for our clothing and fabrics, we of course don’t allow it to go blowing away in the breeze. We harvest the cotton. And in so doing, we have huge quantities of cotton seeds.

Rather than allow those seeds to go to waste, we use them in other ways. We extract oil from them, and the resulting meal is often used for animal fodder. But it makes great garden fertilizer, too!

How Is Cottonseed Meal Made?

Once harvested, cotton goes through processing. First, it’s air-dried to make the material easier to process. Then it goes through the ginning process.

A cotton gin pulls the fibers through fine-toothed combs that remove the seed. This also removes any remaining leaves or other plant waste from the soft cotton.

While the rest of the cotton moves on through the process, we’re left with an abundance of cotton seeds. These seeds go to another location to remove the hulls and extract the oils. Two forms of oil extraction processes are commonly used: solvent, or press.

In solvent extraction, different liquids are used to draw the oil out of the seeds. The seeds are sterilized in the process. Often, there’s still some oil remaining, making them higher in protein and fat. Solvent-extracted seed meal is often used in livestock feed.

Press extraction is exactly what it sounds like. Using a strong press, the oil from the seeds is forcefully extracted. This can be its own separate process or performed before or after solvent extraction.

What remains after the oil is extracted is the cotton seed flour or meal. The cotton meal is then dried and sold as a loose meal. It also can be compressed into cake form, which makes it an easier size for animal fodder. The cake form contains more remaining oil than the meal does.

The hulls that are removed before oil extraction aren’t wasted. Cottonseed hulls are often used as mulch in landscaping. As they break down, they release nutrients into the garden soil as well.

Benefits Of Cottonseed Meal Fertilizer

Cottonseed meal fertilizer provides a healthy kick of slow-releasing nitrogen, potash, and phosphorus. The heavy protein in the cotton meal slows decomposition. Soil microbes have to process the proteins to release nutrients the plants can use.

Because of its slow-releasing nature, you can use higher quantities of cottonseed meal organic fertilizers. There’s no fear of fertilizer burn, making it a safe and sustainable long-term option. And it takes one to four months for it to fully break down, so applications can be spaced out.

The average NPK for this meal is 6-2-2, making it a viable nitrogen option. Different manufacturers have slightly different ratios of nutrients. It’s wise to check the label for your specific brand.

Since cottonseed meal fertilizer has a high organic content, it helps to keep the soil aerated. This reduces compaction in the soil. Soil tilth greatly improves with added organic matter.

Cotton meal holds quite a bit of water when saturated. This makes it a great amendment for water retention in vegetable garden beds!

As well as having a high nitrogen content, cottonseed meal also has many trace minerals. These trace minerals vary widely, but all aid in plant growth.

If your soil is too alkaline, add some cottonseed meal to the bed. It lightly acidifies the soil, which can neutralize soil pH.

Drawbacks Of Cottonseed Meal Fertilizer

The acidifying nature of cottonseed meal can be a drawback. For every 100 lbs of meal used, 9 lbs of agricultural lime is needed to bring the soil back to neutral. Acid-loving plants like blueberries will love the more acidic soil.

If it’s stored in a humid environment, this meal is at risk from molds. Be sure to keep it in a dry, sealed container when not in use.

As cotton is in so much demand by the textile industry, it has another downfall. Many cotton crops are heavily treated with chemicals to protect against insect damage. This means that the seed meal may have pesticide residues.

While there may be traces of pesticides in the meal, it’s limited. Most of the pesticides will be on the cotton itself rather than the hidden seeds or on the plant’s foliage. Very rarely will it actually make it to the seeds themselves.

But it is something to take into consideration. Some states do not consider cotton meal to be a viable organic option for growing produce due to that slight risk. There is an OMRI-rated cottonseed meal available, but it can be difficult to find.

Finally, cottonseed meal contains a naturally-forming compound called gossypol. This isn’t a drawback as a fertilizer. However, if you use chickens for pest control, it might become a problem for them. Gossypol can become toxic for livestock in large quantities. Cottonseed meal should only be fed in limited quantities to poultry (5% for layers, up to 10% for broilers).

If you do raise chickens, it’s best not to top-dress your beds with cottonseed meal. Work it through the soil to prevent your chickens from eating your fertilizer.

How To Use Cottonseed Meal

Since cottonseed meal fertilizer doesn’t burn plants, it’s safe to add larger quantities. It will provide consistent, slow-release nutrition for your plants.

Before planting, you probably want to know how much cottonseed meal to apply. A good rule of thumb is 2-4 lbs per 100 square feet of soil. If your soil is particularly poor, you can go as high as 8-10lbs. This doesn’t have to be exact, but it’s a good estimate!

Work the cottonseed meal fertilizer into the top two to three inches of soil. This ensures you have a good soil-to-fertilizer blend.

Looking to fertilize plants that are already started? New transplants should have one cup of cottonseed meal fertilizer worked into the soil around their root zone. Other younger plants that are already planted will benefit by having a cup of meal added, too.

Older, established plants can take two to four cups of cottonseed meal depending on the size of the plant. Use as a top dressing or work into the soil. Fertilizing lawns with cottonseed meal is also an option. Broadcast the meal over your turf by hand or using a spreader.

Don’t forget your fruit trees or shrubs. Because it also contains potassium and phosphorous, this meal helps promote fruiting. If you’re looking for a larger harvest or healthier fruits and plants, work some meal into the soil there as well.

Regardless of how you’re using it, be sure to water it in generously once applied. This starts the decomposition process that allows the meal to become plant food.

Can I Make Cotton Meal Tea?

To extract the nutrients from this meal, a microbial population has to be in play. It’s not water-soluble.

This means that while you can add small amounts of cotton meal to your compost tea, it won’t add to the fertilizer. It does provide food for the microbial population you’re breeding in your compost tea!

It’s best to put your meal to work directly in garden beds rather than to try to extract the nutrition to a liquid form. The meal acts as a soil conditioner, so it’s most effective that way. You can also use cottonseed meal as food for composting worms.

Frequently Asked Question