Using insecticidal soaps is an organic method of controlling insects in your garden. Although you may be tempted to use dish soap, some dish soaps contain ingredients that may not be good for vegetables. When making an insecticidal soap spray, use a natural soap with no other ingredients. Be sure to freeze any excess because it will spoil, unlike commercial chemical insecticides. Plain soap diluted in water can kill soft-bodied insects, such as aphids. Harder-shelled insects may respond well to soaps with peppers and aromatic roots.
Add 1 or 2 tablespoons of natural liquid soap to a quart jar.
Fill the jar with water to dilute the soap.
Place this liquid in a spray bottle for a basic homemade insecticidal soap.
Add a handful of strong-smelling roots (onions, garlic, ginger) and hot pepper powder to a second quart jar.
Cover the roots and peppers with boiling water. Allow the jar to stand overnight.
Strain the solids out and mix this liquid 1 to 1 with the soap mixture. The resulting insecticidal soap will not only kill and deter insects, but may also be good for deterring deer and rabbits.