Effects of Soapy Water on Plants
For the most part, soapy water affects plants beneficially. Reusing your gray water can be good for the environment, and it contains nutrients as well as fertilizing ingredients for your plants. However, there are a few warnings to note.
The soapy water you get from your sink or laundry, after doing a wash, is called gray water. Gray water can be used to water plants even though it contains soap.
Gray water contains nutrients that will feed the plants. These nutrients can include dead skin cells, food bits, and residue from the soap
Some soaps used to wash dishes contain phosphate, which is a natural plant fertilizer. Also, by using gray water to water your plants, you actually filter any chemicals through your soil, instead of having it pollute the sewer system.
Do not put soapy water in potted plants because their limited soil will turn toxic with too much soapy water, and the plant will die. Also, avoid using soaps with sodium, boron or chlorine as these will harm plants
Use biodegradable soap instead because not only is it good for the environment, but it is much softer on your hands.