I was going thru my plants today and found some powery mildew on them. I sprayed them down with 1.5 tablespons of Neem oil mixed with 3.5 quarts of water. Did I do the right thing?
its up around 50-60% which is high I have them under a 400W MH but with temps in the 60's and rain its not helping warm up my room. I have 2 fans blowing 24/7 and am running my home heater to warm up the room
PM can manifest at any humidity. Botryitus (sp?- gray mold, bud rot) needs a higher humidity to grow.
Neem will work to control the PM, but it will always come back on new growth and after the treatment wears off (2-3 weeks). You also need to make sure the plants are thoroughly covered, as any spots you miss will be covered in PM quickly. Also use it when your lights are just about to fire up, or IMMEDIATELY after they do fire up, or you run the risk of burning the foliage. I wouldn't use neem the last couple weeks of flowering, as it makes your meds taste like shiza.
I prefer GreenCure over neem oil.
Personally, I have yet to try these products but a member, NCGA, suggested them to me for my PM problem. One is Sonota and the other is Oxidate. Both can used late into flowering and will kill it on the spot, supposedly. I am ordering a couple bottles of each and will testing them out this outdoor season. They're not systemic like the Banner Maxx or Eagle 20, but they are supposed to work very well according to NC and they are not toxic chemicals like the systemic fungicides. I wish I could say if they work from my own experience, but I will see soon enough, I just wanted to throw these other options out there for you to think about. NCGA, seemed to really know his shit about the subject and might be someone to PM if you have more questions.