HYDRO *HELP* 1st week of flower and signs of PM

[Jordan]

I need help and guidance from some seasoned growers in experience with White Powdery Mildew..... So this the first time in my life that I got PM and I am 1 week into my flowering. I have a 20x30 grow room with 24 lights. My had humidity issues due to a HVAC failure. I got it fixed and I am keeping the Humidity levels around 40-49% now. I used Nuke Em flying skulls and 4 days later a copper soap and it did nothing.
I am about to spray 70% Neem oil on all the plants. I did a big fan defol to open up the canopy to help air flow. I have a OSC Fan over each tray to keep air flow through my canopy.
I am getting an room air exchange every 4-5min as well. Im growing in Rockwool Hugos, keep room temp at 75-77 Degrees when lights on and 72 degreess when lights off and humidity at 40% when lights off to keep spores dormant?
Can anyone guide me on what to do? I have been trying to kill this PM, Its just on the under side of the leaves and its white. I don't want to kill all my plants... Can I save this room and still be able to have a successful crop? Please help.

[vostok]

PM is no biggy...but can lead to more serious fungal infections,
reduce watering reduce humidity and apply neem oil is what I say...
and you have done that

I hope you post back

good luck

[Fluxuated]

Are you using regular tap water in the Humidifier? That will spit out white powder. Try distilled water and it shouldn't happen anymore. I'm new myself, but I had that problem at the beginning of my first grow. Hope you fix it.

[Jordan]

I only am using dehumidifiers Im pulling prob 400 pints a day plus my AC is pulling

[alltatup]

Hi Jordan One word: DEFOLIATION. Learn how to do it properly and you won't get mildew. Here's GWE's guide: https://www.growweedeasy.com/defoliation

Each grow room environment is different, so you have to "tweak" defoliation depending on various factors in your environment. For me, although the tutorial says to defoliate right before the switch to 12/12, and then again 3 weeks later, there is no way I can let all the leaves keep growing during those 3 weeks, because they overlap and start sweating on each other, which I know will lead to mildew. So, just about every day I have to remove some of the abundant leaf growth or there won't be any air circulation, there will be too much leaf transpiration which increases humidity, and all the problems that follow from that.

My guiding principle is to leave as many leaves as I can and only remove the ones I can't tuck. We want the leaves to power the stretch, but we don't want mildew!! Go over to GWE and read about how to treat the mildew, because if it stays, it will make the bud toxic. Unsmokeable.

[SoOrbudgal]

Good advice from alltatup. I do it with my autos and photos when they are crowded they can't overlap each other.

[Jordan]

I lollipop everything before 12/12 flip. I noticed the PM after I had to HVAC failure and it was over 70% RH. I neemed it. It looks like it did help abit. im still finding some under the leaves but not as much before but still there. There is no PM on the top of the leaves I have the humidity in check. I heard that you can use a 35% H2O2 mix with water to spray the leaves as well. Anyone use that method before?