Kaolin Clay

There aren’t many things that we spray at LaFarm. But in the wake of the storm it is more important than usual for us to do everything we can to protect our plants from any further damage. That’s why right now, when the worst of the pests are around, we’re protecting our most vulnerable crops with Kaolin Clay.

Kaolin Clay is a completely organic substance, it is in fact a finely ground clay powder. When mixed with water, Kaolin Clay can be sprayed on plants to coat them in this powder, which (with an effectiveness that surprised me) confuses pests, who confusedly find that instead of a tasty eggplant leaf, they’ve landed on a weird clay bush. This way, it doesn’t actually kill anything or disrupt the ecosystem, it just protects the plants you spray it on.

Kaolin Clay is not completely effective for all plants against all pests, but it’s definitely effective enough that we spray our squash (especially young transplants) to protect against cucumber beetles or squash bugs, our eggplant to protect against flea beetles, Colorado potato beetles or anything else that might want a munch on them, and on a few others like Brussels Sprouts.

Stirring Kaolin Clay solution with the broken handle of an old digging fork.

To use Kaolin Clay, you first need to mix it with water. We go for the Surround brand Kaolin Clay, which calls for 3 cups of Clay to be mixed with every 1 gallon of water. We put the Clay in a bucket and then add water and stir until the Clay is mixed enough that it doesn’t stick to the bucket or whatever we use to stir. Also at this step it’s safest to wear something over your nose and mouth; although the clay is not toxic, you still don’t want powdered clay getting in your lungs.

It is most advisable to spray on days without direct sunlight. When the liquid pools on a plant, it can magnify sunlight, which can burn the plant, making it less healthy, defeating the purpose of spraying. At the same time, you do not want to spray if it’s going to rain soon. Rain can wash off the clay, especially if it’s been applied only recently.

We use a hand-pumped backpack sprayer, dumping in the mixture from the bucket once it’s ready. It’s theoretically possible to spray it from a smaller spray bottle if you only needed enough for a plant or two. Some farmers will mix fish emulsion into the clay (fish emulsion can soak into the leaves of mature plants, giving them additional nutrients) but this is not advised by the USDA. It’s important to spray every leaf of any plant you’re trying to protect, and both the tops and bottoms of each leaf. Otherwise it would be like building a wall around half of a town to protect against invasion: it won’t help when they come from the other side.

: Sarah diligently spraying Surround on our eggplant

: Each leaf should be coated with the white clay

: Once it drys, the clay just makes a plant look a few shades lighter than it used to be.

After spraying, most pests will be confused by the clay and not eat your plants. That is especially important if you have hail- and flea beetle-damaged crops like our eggplant, or if you’re about to transplant 50 zucchini when you’ve noticed some cucumber beetles around the farm.

Happy Farming!

-Joe Ingrao, Summer 2015 EXCEL Scholar

Organic Pest Control Research at Lafayette College by Julia Seidenstein

Hi folk,

During the summer of 2011, Julia Seidenstein ’15 was a Mellon Scholar working at the Lafayette Community Garden and Student Farm. She focused on testing several pest control methodologies, many of them in Community Garden plots marked out with small flags.

Abstract: During the summer of 2010, much of the Lafayette College Garden had pest problems. Conventional farming uses pesticides and insecticides that kill the pests, and can also kill beneficial bugs and leave chemical residue on food and in the soil. This leads to possible health problems and pollution of water by run-off from farms. Organic pest control methodologies are different than those of conventional farming. During the growing season of 2011, organic pest control methods were implemented. Many of these methods showed positive results in reducing the amount of damage the pests caused. The results from the test plots and student garden of the 2011 summer growing season are to be discussed.

Here is her Bug Encyclopedia and here is her Implemented Organic Methods that she tried.

Click on Julia's research poster for a larger view.

The Role of Pesticides in Community Garden Pest Control

Hey folks, today I have a guest post to share, written by a fellow gardener, Sam G.

There is no doubt that a community garden or student farm has different requirements for care than a large commercial operation. That being said, there are several problems such as pests that impact both small operations and large scale agricultural concerns equally. However the solutions that many commercial concerns have used for their pest problems are not only harmful to the environment but also would be far too dangerous to use by those who are tending to a smaller plot of land.

With that in mind let’s examine some of the healthier and saner options for pest control that are well within the reach of any sized farming or gardening operation. Here’s a list of some of the non-toxic pest control options that can protect and enhance a community garden or farm.

#1 Think About Prevention First

While pests are a big problem in any garden or farm, sometimes you can avoid the problem all together by being prepared and preventing them from getting in. Obviously this is incredibly difficult when you have a large open space, but there are a few measures you can take that will make your green spaces much less attractive to pest species. The best thing you can do in this case is to apply an organic repellent such as hot pepper extract more info on which can be found at this site or similar products around the perimeter of your space, to keep bugs, snakes, rodents and other pests away.

Being sure to keep your plants healthy is also a great way to keep several types of insects and other pests away, as healthy and robust plants are much less likely to attract opportunistic insects than a sick or damaged plant is.

#2 If Repellents Don’t Work, Use A Natural Solution

Despite the fact that pesticides have a well-deserved reputation for doing more harm than good for many farms and gardens, there are a multitude of products that will still deal effectively with pests but will not cause the same amount of harm to the environment, or your plants for that matter.

Two of the best products for natural pest control are rosemary oil and peppermint oil. They have much the same effect as chemical pesticides when sprayed onto plants, but are completely non-toxic to humans and other mammals and best of all are not toxic to aquatic life. This lack of aquatic toxicity has huge implications for gardens and farms that are located near sources of freshwater or use extensive irrigation that would make the use of more toxic products a bad idea.

Another great topical treatment for many pest problems is diatomaceous earth, despite the fact that it is completely safe for humans, even if it is ingested, it is quite toxic to insects, and can be used to get rid of virtually any sized infestation in a garden or farm setting. Because of its low toxicity, it won’t be dangerous to eat plants that are treated with the product, which cannot be said of many other topical pesticides.

#3 Encourage The Predators Of Pests

This is a quick and simple way to gain control over any pest problem with a modicum of effort on your part. For any pest, there are likely to be a large number of natural predators that can reduce or even eliminate their numbers, particularly if they are used in concert with other organic pest control methods.

For instance, you should encourage animals such as cats to hang around your garden or farm, in order to keep mice and snake populations down. Although even snakes can be helpful in their own way if they are eating any rodents that might be intruding on your plants. However you should be careful to not encourage the presence of poisonous snakes because obviously that can cause issues above and beyond those posed by rodents or insects.

Author Bio

Sam Gerald is an amateur gardener who is concerned with the role pesticides play in today’s agricultural scene. He advocates for using natural and organic solutions to pest control problems whenever it is feasible. Click the following link to learn more about some of his favorite natural and organic pest control products.