I fill a bottle that I think holds 16 oz. with tap water and usually have some suds coming out the top from the last batch, then I add a squirt of dishwashing liquid. See how carefully I measure? I then put the top on, shake it up, and spray away. For some things I'll add a capful of rubbing alcohol. This stuff also cleans up dirty spots from spills when I'm working with my plants indoors really well too. I've seen no adverse effects from using it as frequently as needed. When I was treating a ficus for scale I think I sprayed every day for over a week with the soap and alcohol. At that point I did try to keep the soap from getting into the soil.