I've always used plain dish detergent. Dawn, Joy, we buy Ajax brand. NO added bleach or anti bacterial stuff. That's the only kind we buy so I can use it for plants and the dishes. I've had plenty of experience with PM as my wife has a phlox plant that has been highly susceptible to it. This year was an exception. No PM and actually they are in a second bloom right now! Most Excellent! It's also been a very good year for bug pests (meaning, very few bug problems) Even house flies have been few.