Help! Elemental sulfur & Powdery mildew

I want to go and get some sulfur from the local supermarket. But was wondering how do I give it to my plants? Do I put in water, I'm hearing burn it... Can n e 1 out there help me out? This is my first time and I don't want my first batch to get ruined :( What Is the best and cheapest way's? They are just starting to bud. I put them last week on a 12/12. I sprayed a little of baking soda and water soap mix did 1/4 teaspoon baking,1/4 liquid soap/1 quart Water. Mixed and sprayed. Am I going to ruin the plant or will that help? Any good advice from some of you experts out there? MUCH APPRECIATED
Thanx my fellow Pot Lovers !! :jointsmile:

I'm new too, but when you say sulfur, do you mean fertilizer?