How to Make Homemade Insecticidal Soap for Plants

Castille soap next to green leaves for making homemade insecticidal soap
Use pure, natural soap and water when making insecticidal soap for your plants. (Antonio Gravate)

Thanks to insecticidal soap, controlling soft-bodied insects in your garden and on houseplants has never been easier!

Here’s a simple recipe for making your own homemade insecticidal soap using ordinary household ingredients.


Spray bottle spraying homemade insecticidal soap on plant leaves
Homemade insecticidal soap is all-natural and easy on plants. (Jupiterimages, Photo Images)

Homemade Insecticidal Soap Recipe

The simplest insecticidal soap is nothing more than a 2-percent soap solution. To make this at home, you will need:

  • Sprayer: Any clean spray bottle or garden sprayer will work fine for spraying insecticidal soap. Make sure the sprayer or bottle hasn’t been used for herbicides.
  • Pure Soap: Use a pure liquid soap, such as Castile, or all-natural soap. The active ingredient in insecticidal soap comes from the fatty acids in animal fat or vegetable oil, so it’s important to use the real thing. Don’t use detergents (which aren’t actually soaps), dish soaps, or any products with degreasers, skin moisturizers, or synthetic chemicals. Dr. Bronner’s Pure Castile Soap is usually pretty easy to find in stores or check your local natural-foods store for other options.
  • Pure Water: Tap water is fine for making insecticidal soap. If you have hard water, you may want to use bottled water to prevent soap scum from building up on your plants.

To make homemade 2-percent insecticidal soap, mix together:

  • 5 tablespoons soap to 1 gallon of water

OR

  • 1 heavy tablespoon soap to 1 quart of water

Other ingredients can be added, such as crushed red pepper, canola oil, apple cider vinegar and garlic powder. (Photo illustration using images from Getty Images)

Homemade Insecticidal Soap Recipe Variations

Like any other home remedy, there are as many variations on this recipe as there are gardeners! You can also try:

  • Diluted Solution: If the spray causes damage or burns your plant foliage, cut the amount of soap in half and try a 1% solution. This is the concentration usually found in commercial sprays. The lighter solution might be less effective but is gentler on plants.
  • Cooking Oil: To help the solution stick a little longer, add two tablespoons of light cooking oil (such as corn, canola, olive, or safflower) per gallon of water to the mix.
  • Vinegar: To make a spray that also targets powdery mildew, add a teaspoon of cider vinegar per gallon of water to the mix.
  • Garlic or Pepper: To help repel chewing insects, add a teaspoon of ground red pepper and/or garlic per gallon of water to the mix.
  • Bar Soap: For a less-exact recipe, drop a bar of pure soap (such as organic bar soap or Ivory) into a gallon of water and leave it overnight. Remove the bar and shake well before spraying.

Further Reading