Green Cure is my choice for controlling Powdery Mildew. Most Hydro Shops will stock it. Your next best Choice is Baking Soda. 1 tablespoon per gallon of water is the ratio for both products. BNW
Had a bout of PM on one of my ladies. I used green cure as a foliage spray per the directions, I also did a bath at harvest (mix correct ratio of mix in a 5 gal bucket with room temp water, 1 bucket of clean room temp water and I soaked the fresh clipped buds in the green cure mix for about 10-15 seconds and rinsed off in the clean water. Immediately shake excess water off...hang and get a fan on the buds to keep moisture down) it worked wonderfully. Good luck
definitely going to be trying the bath for my buds this year. Most wont have any PM or problems, but better safe than sorry. Not much Bud rot going on, but theres has been little bits of PM since the start of flower, im using greencure but at a low concentration, it burned some leafs when I did the two scoops per gal.