I have done an experiment on this very topic and as a matter of fact the plants watered with soapy water grew better than those watered with regular water
Does Soap Affect The Plant's Growth?
Yes because of the phosphate thats in the soapy water.It can be harmful to the plant.
I have no clue what so ever. I'm doing this project also and still don't understand. Does it matter what kind of soap I use or what? Because I am confused and could use some help!!!