The bath works...no doubt about it...it should even seem strange...Outdoor grows get rained on all the time, as long as your gentle with the plants it works fine... for your vegging plants, here's a mixture to spray the girls with.... Warm milk, neem oil, garlic and PH up.. Let the milk sit outside the fridge for a day, add neem oil, and crushed garlic. Let the lovely mixture sit for another day, strain ad PH up . check plants for PM and REMOVE any fan leaves with it, then spray...repeat in 2 days, repeat again in 2 days...Most likely PM is a result of lack of circulation, and/ or excessive humity. Add fans and possibly a dehumidifier...
Stupid mildew!!! I do all-rh at 30, temps at 80, fans, lolipop, but still battling. Trying heat-100 for an hour. Next sulphr burn? Help
You might want to try a product called BAM (beneficial active microbes) it's organic and is very safe to use, I live in the tropics and it has been a real crop saver. You can use it as a preventive massure 2 oz per gallon of unclorinated water or a 1 to 4 ratio for more advanced symptoms and a 50 to 50 ratio for extreme problems. I found that you can spay it as much as needed and won't harm the plants. hope that helps.
All powdery mildew fungi require living plant tissue to grow. The important thing about this disease is all powdery mildew species can germinate and get infected in the absence of water, even though humidity requirements for germination vary. Powdery mildew - How to Get Rid of Powdery Mildew on Plants