Q: Is it possible to make your own insecticidal soap spray? Can you provide a recipe?

A: I once tried to make soap from lye and lard. The results ruined a boiler pot, melted the hair on my arm and stank up the house something fierce. You might think you can make a safe insecticide from soap but it’s more complicated than you think.

The first fact to remember is that a detergent is completely different from soap. Almost all household washing materials (Dawn, Joy, etc.) are detergents. Even bar soap may contain detergent chemicals. At concentrations strong enough to kill insects, detergents WILL harm plant leaves.

One recipe is one tablespoon of pure castille soap per quart of distilled water. Test on an inexpensive plant before spraying your whole garden. Do not spray on a hot day. I think you would be better off to use a manufactured “Insecticidal Soap Spray”. These products are tested thoroughly to make sure they do not harm plants. The soap kills young insects like a charm.