WOW, I cant believe the rude attitude you got, how disgusting.
Ummm and wtf, people giving you shit for using milk as a treatment for powdery mildew, well you know right there if they don't know something that basic, why listen to anything else they say. Gosh at least look things up if your gonna sling shit.
Oh and the for those who seriously don't know this. Powdery mildew happens outdoors. I mean really, where did the idea this is solely an indoor issue come from (insert rolling eyes)
Sulphar is a good treatment if you are not flowering, but for a mild case seriously the milk mix is all you need. Just make sure its skim milk, or 2% fat, and mix 9 parts water to one part milk. And ofcourse this gives a little extra calcium to the plants that they love. I have done this personally and had great success.
If it doesn't seem to clear up, and starts to get worse, just go get some sulphar and spray it on.
Has it been wet in your area, or high humidity, that would cause it.