As I do more reading though, I find warnings that many dish detergents will harm plants. Some people do spot tests, but buying a commercial insecticidal soap is safest. I guess I’ve been lucky, maybe because I use a crunchy natural dish detergent that is pretty mild.
I don’t know what you consider regular soap, but my understanding is that liquid soaps typically have potassium, bar soaps may use either. But I was using the term pretty loosely, people often make homemade insecticidal ‘soap’ with dish detergent which isn’t technically soap at all. Any surfactant tends to kill insects by compromising the waxy coating that keeps them from drying out.
You can’t use regular soap; insecticidal soaps are fatty acid salts with potassium, while regular soaps are made with sodium.
As I do more reading though, I find warnings that many dish detergents will harm plants. Some people do spot tests, but buying a commercial insecticidal soap is safest. I guess I’ve been lucky, maybe because I use a crunchy natural dish detergent that is pretty mild.
I don’t know what you consider regular soap, but my understanding is that liquid soaps typically have potassium, bar soaps may use either. But I was using the term pretty loosely, people often make homemade insecticidal ‘soap’ with dish detergent which isn’t technically soap at all. Any surfactant tends to kill insects by compromising the waxy coating that keeps them from drying out.