How to Mix Homemade Insecticides Into Soil

Pests can be a problem for any gardener in any climate, but if you ascribe to an organic philosophy, you're not going to run out and buy a bottle of insecticide to deal with the problem. Fortunately, Mother Nature provides some alternatives. Many homemade insecticides are made by mixing water with neem oil, soap, hot peppers or other substances. Another option is to work a small amount of diatomaceous earth into the soil. The material, made up of the fossilized skeletons of marine creatures, can kill many types of bugs but will keep your beneficial earthworms from harm. Whether you use this method or some other concoction, take some precautions to protect your health before the application.

Dust mask

Gloves

Protective clothing

Bulb duster

Spray bottle

Neem oil

Organic liquid soap

Cayenne pepper

Citrus essential oil

Put on a dust mask to protect you from inhaling the dust of diatomaceous earth, which may cause respiratory problems. Follow this precaution for any other substance you may add to the soil as well.

Wear gloves, long pants and a long-sleeve shirt. Diatomaceous earth, as well as soaps, peppers and other substances, can cause skin dryness, which can lead to skin irritation.

Put your diatomaceous earth into a bulb duster, if you're applying it to the soil dry. For a neem and soap solution, put 1/2 ounce neem oil, 1/2 teaspoon organic liquid soap and 2 quarts warm water in the bottle. For a pepper solution, add 1 teaspoon of cayenne pepper, 10 drops of citrus essential oil and 1 cup of water to the bottle.

Hold the leaves of any plants away as you squeeze the bulb duster around the perimeter of each plant. Blow enough dust to leave a 1- to 2-inch whitish strip around the plants. Also blow a 1- to 2-inch strip around the perimeter of the garden. If you're using a spray, spray the surface of the soil with your mixture, entirely coating the soil -- and the leaves of the plants -- with enough spray to make the surfaces slightly wet.

Repeat the application of diatomaceous earth after it rains, or after you've watered the garden, since it stops working when the diatomaceous earth gets wet. For this reason, an underground irrigation system would be ideal. That's also why it's not ideal to mix the diatomaceous earth into the soil, since it will get wet. For sprays, re-apply the spray to the soil and plants roughly every two weeks.

When you're dealing with pests, it's always best to figure out what type of pest you have before mixing up a remedy. For example, neem may be better for aphids or beetles, while soaps may be the trick for flies and mites as well as aphids.