How to Make an Insecticide


You can easily, and cheaply, make your own safe soap spray insecticide. Insects will be repelled by plants treated with insecticidal soap, especially soft-bodied arthropods such as aphids, green flies, mealybugs, plant lice, scale insects, spider mites and white flies. But it won't affect most beneficial insects like bees, lacewings, and ladybugs, and it won't hurt birds or other predators. Castile--a natural, all-vegetable, non-detergent type of soap product--won't expose plants, wildlife and the environment to the damaging effects of detergents. So, you'll kill pests without damaging the environment.

Step 1

Grate a large bar of castile non-detergent vegetable oil based soap into a large pot.

Step 2

Add 1 gallon of water. Bring to a boil over medium heat, stirring constantly. Reduce the heat and simmer for 10 minutes, stirring constantly.

Step 3

Allow the insecticide to cool to room temperature. Funnel it into a 1-gallon plastic container. Store in a cool, dark location indefinitely.

Step 4

Shake the insecticide concentrate well when you're ready to use it. Combine 1 oz. with 10 oz. of water in a plastic spray bottle.

Step 5

Apply early in the morning, if possible, to give the solution time to dry. Use on garden plants you think are attracting pests. Never apply any liquid to foliage in hot weather--even water--to avoid leaf burn.

Step 6

Repeat weekly and immediately following rainfall.

Tips and Warnings

  • Predatory mites--a major natural control for spider mites--are easily killed by any insecticides. Don't use this recipe on plants that may be sensitive to it, including bleeding heart, cherry, chestnut, crown of thorns, most ferns, gardenia, hawthorn, mountain ash, nasturtium, most peas, sweet pea and most violets.

Things You'll Need

  • large bar of castile vegetable oil based soap
  • Funnel
  • Empty plastic gallon container
  • 16-oz. plastic spray bottle


  • All About Insecticidal Soaps
  • What's the Difference Between Soap and Detergent?

Who Can Help

  • Homemade Organic Insecticides
  • Make Your Own Pyrethrum Insecticide
Keywords: insecticide, homemade insecticide, homemade garden insecticide, how to make an insecticide

About this Author

Axl J. Amistaadt began as a part-time amateur freelance writer in 1985, turned professional in 2005, and became a full-time writer in 2007. Amistaadt’s major focus is publishing material for GardenGuides. Areas of expertise include home gardening, horticulture, alternative and home remedies, pets, wildlife, handcrafts, cooking, and juvenile science experiments.