Powdery Mildew....

Son of a bitch, and everything was going so smoothly....

So I have this large Trainwreck (HP, 5 gal DWC) about two weeks into flower. She's bushy as hell and I'm having issues with air flow (I was concerned because the past few days have been hot as hell). I noticed a few spots of powdery mildew on some cuttings I have in a different room of the house and decided to check my plant...sure enough there are a few spots showing.

I had an issue with some wilting/chlorosis on the bottom of the plant earlier in bloom (switched to bloom nutes too quicky) and the damaged leaves seem to be the ones that are showing the most. The spots are very faint, there are only a handful of them that I can see and you certainly have to be looking hard to see anything at all, but it is no doubt afflicted. I pinched off the few leaves that showed symptoms.

I've been doing some reading on controlling this beast (gonna pick up some apple cider vinegar tomorrow), but what's the bottom line? How dangerous is powdery mildew, will I be able to salvage a good yield if I take action with AC vinegar? What are some other options for combating it (I've read of many, but am looking for some personal experience)? Can I spray the whole plant down with the vinegar without affecting the taste of the final product (I'd imagine not, but the baby buds are all over the damn place and it's gonna be hard to hit only the leaves)? For the record, temps are high 80's (which didn't really seem to be bothering her, no signs of heat stress) and RH is around 50-60% (which doesn't seem too bad, I suspect the infection rode in on my person from the area where the clones are).

Here's a pic of the whole plant taken a few days ago, just to give some perspective on how bushy she is and why fresh air is such a bitch...I'd love to remove a shitload of the wilted foliage on the bottom, but I'm afraid that doing so might stress it and cause it to drop nanners.

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Please help!



T

Eagle 20

Definitely not in bloom, and most experienced growers try to use Eagle 20 as a last resort.

Instead, use one part skim milk to nine parts water and foliar spray the entire plant. This can be done up to the day of harvest.

A weak solution of Physan 20 in a spray bottle is an excellent way to hit those few PM spots you may encounter occasionally. This is not recommended in bloom by everyone, some are fine with it.

She is a lovely beast!!! Fan fan and more fan. The more air movement the better. Good luck bro. She is lovely!!

If you want to try something that won't hurt your buds or change the flavour, try a 15% milk (1% milk)/filtered water solution. I used it last round when I got some PM on one strain towards the last 2 weeks. It worked to keep it in check, doesn't remove it but kept it from getting worse. I cleaned up after the run and culled anything that could possibly have PM. This run as a precaution I've been spraying them weekly in veg with a mix of 1/2 tspn Baking Soda, 1/4 tspn dish soap, 1/4 tspn Olive Oil, in 2L of filtered water. Baking Soda works by changing the PH on the surface to a level where the PM can't grow. No damage to the leaves/plants from my observations. I also found out the hard way that some strains like PM and some strains are somewhat resistant to it, I won't grow that Platinum Bubba Kush strain again as it was a PM magnet.

That doesn't look like powdery mildew to me at all....just looks like your leafs are drying up from poor air flow .....or else I just can't c it in the pick......if it is pm you can treat it with backing soda..and a light cloth..

Thanks for the input guys. Scarecrow, you can't see the PM in the picture, you can barely see it looking right at the plant, the leaves are in such bad shape from switching to bloom formula before the stretch.

I'm gonna get some skim milk and give that a shot. She has at least 5-6 weeks left before harvest, do you guys think I'll be able to keep it in check until harvest if I stay on it with the milk and other solutions mentioned? I have no delusions about the seriousness of PM, I know that no cuttings can be salvaged and I'm fine with that just so long as I can get her to harvest. I was expecting a respectable yield due to her size, am I right to assume that fighting off the mildew will lower yield?

Thanks again guys!

If it's only starting now try and fix your air flow .....because it will gett a lot worse as it's flowering....run your lights at night and off during the day...it's a lot easier to control the climate.....I know baking soda mixed with tap water works very good but I'm not sure with flowering plant ..the baking soda changes the leaf surface to a ph of 7 ...pm can't survive in it.....try fix your airflow ...IMOIMO

Yea I put a new fan in there and I do run my lights during the night (well, from 4pm to 4am).

I just applied the first skim milk treatment. My god, it's very difficult to hit every leaf with a plant so full, I tried my best to hit only the leaves and not the flowers, but that was impossible. How often do I apply the milk, daily, weekly? I've also read that PM can build tolerances to treatments, should I switch between milk and baking soda or AC vinegar every treatment? Again I really appreciate it guys, this is my first grow and I was so proud of that damn plant...this is a real drag man, I feel like I have a kid in the hospital.



T.