Hello fellow cultivators:
I’m a rather experienced grower so I must admit I feel a little embarrassed that I haven’t been able to control this problem efficiently, however, at this point I’m a little desperate and could really use the collective advice of the other experts.
So I run a small commercial grow and have been successfully growing a beautiful strain of White Widow (among others) for over a year now without any issue. Started by germinating them and have cloned off ever since. They live in an ebb and flow hydroponic system, underneath NextLight Mega Commercial series LEDs at 690, are fed a carefully calculated nutrient program using General Hydroponics nutes in a ventilated, circulated 74 degree, 45% humidity environment. We have always brought them from clone to harvest beautifully.
About a month ago we started having trouble controlling the temperature and humidity in our White Widow grow space. (our main dehumidifier broke :-/) The humidity at times reached NINETY PERCENT on the overnight. We got a new dehu and nipped that shit in the bud. However, that set the stage for this righteous powdery mildew problem. Because we’ve never had fungal problems before I was not necessarily prepared and that’s my bad.
We started off by clipping the leaves with visible PM and then using NorCal Plant Nutrient’s 86 spray (combo of rosemary oil, lemongrass oil, cinnamon oil and cottonseed oil, polyglycerol oleate, glycering, lauric acid) right before the ladies went to sleep but started noticing significant pistil burning. Plus the smell was incredibly offensive and I was really concerned about how those oils were going to affect the taste, smell and presentation of my final product.
That’s when I moved on to food grade H202. I went branch by branch, bud by bud, with an H202 soaked cheesecloth and mechanically removed every bit of PM I saw. I tested a diluted H202 mix on half the plant and straight H202 on the other half. I did notice a significant reduction in the PM but I also questioned how the mechanical scrubbing was going to affect my trichomes and if the possible “scrubbing” was going to impact my leaves ability to photosynthesize.
I created an H202 foliar spray and sprayed another plant before bedtime.
Both plants, the one I “scrubbed” and the one I sprayed presented with significant pistil burn the following morning.
So yesterday I tried a baking soda solution. I figured I’d try to “meet in the middle” between spraying and scrubbing and I saturated a q-tip with the H202 dilution and rolled it on. Now at this point, some locations of my plants had PM on my sugar leaves and REALLY, dangerously close to the buds. (for all i know it was growing inside my buds.) So I did use my saturated qtip to kind of get in there but I didn’t scrub or get aggressive or anything. I legit rolled it on/rolled it in.
This morning I show up to the lab, go to check the girl and her pistils are all kinds of dried up and brown. This is NOT the normal browning that occurs towards the end of flower. We’re not even there yet, plus that doesn’t happen overnight at this extreme.
I’ve done pretty much everything that every forum, article, textbook and bit of advice that’s been given to me (and within my capacity), but for whatever reason every single thing I do leads to my plants getting burnt. What the hell is going on?? Why does everyone and everything recommend these solutions but my plants are burning to a crisp?
I mean, I know that the only real way to mitigate a PM problem is to control my environments to avoid the growth of PM to begin with, but unfortunately that moment has come and gone. I just don’t know how to properly manage my current PM issue WITHOUT destroying an entire strain crop!!
Could all of you wonderfully expert and experienced growers help a woman out over here? I truly appreciate your collective advice.
(if y’all need to see some photos just let me know. I’ve been meticulously documenting this entire process.)
Thanks in advance!!
Hello fellow cultivators: