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mildew prevention

12HourPower

12HourPower

New member
Looking for product or mix-it-yourself IPM recommendations for powdery mildew prevention during middle to late flower. I use neem oil for my veg leaves but that is not an option now that budlets have formed. Is there anything that 1) won't leave an unpleasant residue, and 2) actually works for PM
The humidity has been very high here and there is a lot of spore in the air outside. Inside the room, I have been policing my plants enough to catch individual spots of PM before they have a chance to spread. The environment has been remedied by a dehumidifier and AC (my electric bill is gonna be 💀). Now maintaining 74-75°F and 45-50% RH pretty much around the clock, with night being slightly cooler by a degree or two. Also the door no longer needs to be open to the rest of the house 24/7 so I'm hoping that cuts back on the spore traffic.

I'm not being overrun for now but I sure would like to add a second line of defense to the environment control. Also could someone tell me where to edit my signature, I can't find it in the menus.
 
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Howdy neighbor i'm down in Roseburg. Hell of a freeze you all had. Had my daughter staying with me for 7 days cause of power outage. For the last 4 days it's been like 65f crazy flux. Anyhoo I've not experienced PM issues at your level. I have central heating 70f in a less than 900sq ft home. My humidity in my tent is between 45-52% not the best and i will put a small clamp on CFL 50watt when and if the temp goes below 65f. I use a rotating fan on the outside of my tent but most folks have had a clip on inside i would highly recommend you use one. Are you growing in a tent? I'd use clorox wipes to wipe down the tent and or remove those plants from the room and spray some lysol kills mold an mildew. Hang in there others will chime in.
 
You have 45-50% RH in your tent with no dehumidifier? That sounds like a dream.

Yes, I am in a 8x8x6.5 ft tent inside a 12x12 bedroom at the end of the house.
 
WoW huge setup. No i grow very simply i don't ever use humidifier it's rather dry inside my little house. I've mostly grown outdoors all my life.
I've had to place wet towels and pots of water when i use to use wood heat. My main concern is keeping the heat up, for that i use a clamp on 54watt CFL with a reflector, same one i use for seedlings. Wish i could help more with the editing, hopefully someone with more tech brains will chime in.
 
I have WPM all year round here in my outdoor garden. Nothing I can do about that than grow indoors. I use a humidifier during early veg and need a dehumidifier during flower. I know of no magic spray that you can put on flowers to stop it and still smoke the flowers. Everyone who grows outdoors around me has had total losses to WPM and mould the last three seasons.

It's easy to control indoors...Outdoors depends on your climate. It's too wet here.
 
Fans for air movent/flow and trimming for the same reason. [edit] for wpm you have moisture where its forming, below 50% humidity you should not have moisture on the plant)[/edit]
One could try "trifecta crop control" which claims to be safe as well as organic. I have used it for bud rot control some years ago (really wet fall here), IF you want to spray something read up on it an make your own choice. Is anything sprayed on your buds really safe? (organic or not)
 
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I forgot to mention, the few spots I found all appeared within the last few days, following 3-4 days of RH of 55-65% due to volatile outdoor weather. I was fretting hard, hence the AC and DH. Still not pleased with the electric consumption, but the environment is super stable now. My neighbor was curious why I didn't just open the window and put a box fan in it, I was like "are you insane?! The moisture and spores are coming from outside!"

Anyhow, now the air is moving superbly at 75F and 45%. They just woke up a few minutes ago, I am going to check for leaf lay and wet spots (and everything else).

That's a bummer about your outdoor garden. You must be in the Midwest or Southern states.
 
Thanks for the suggestion. I will inspect that one. I was considering crop defender 3 which is basically rosemary, thyme, peppermint, and clove essential oils mixed with water and organic emulsifiers. Not sure how that has antifungal properties as it's listed for use against pests AND mildew. I know a grower who mixed his own version of that and swore by it. But I don't think he used it during flower. His garden experienced dry summers, he probably didn't need or want to use it in his outdoor hoop house(s).

​​​​​​I won't resort to anything being sprayed unless my environmental intervention doesn't work. But honestly, I think it will be okay now. It wasn't even a problem for literally months, until one day the humidity just shot through the roof, and then poof. I got to say though, none of the spots I find are anywhere close to as severe as most pictures of WPM on the web. 🤞 🤞 I will stay vigilant
 
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Welcome to GWE BTW
Here my humidity can be 100% (I grow outdoor), so I thought I would try a "mildew resistant" strain, it was the first to have WPM that year! It was back to air flow.
 
"Now maintaining 74-75°F and 45-50% RH pretty much around the clock..."

That should do it for avoiding WPM. If you previously had a bad infection clean everything in the tent and lung room before starting a new grow. As is often said, an oz of prevention is better than a pound of rotten weed. Lots of internal air circulation inside the tent. I use multiple 6 inch clip on fans. Keep the air moving.

To edit your signature:
click on your avatar in upper right
open my profile
click on edit settings
select account tab
scroll down to Conversation Detail Options
click on edit post signature
enter signature
click save
 
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From memory spores need a certain RH% to germinate. I think around 60% or above but not sure. If you can keep the RH in your buds below the spore germination point you won't get moldy buds.
 
"If you can keep the RH in your buds below the spore germination point you won't get moldy buds"

I'm guessing that means a room RH of 45%, to keep the buds below 60%.
 
Depends on temps, the size and density of your buds and airflow so it will vary but I'd say at 45% you should be pretty safe in late flower. We are talking big buds though
 
IMG_20240213_142845796.jpg

​​​​​This is wpm on grass and blackberry a few km from my house where I walk the dog. It's like this in most low areas where water and fog collect. I put my outside clothes in the dryer for 15 minutes when I get back home. I have stopped it inside the tent, but it took 10 days of lower humidity conditions to abate.
IMG_20240213_142852981.jpg
 
1 to 3 milk to water in a spray bottle. Shake well and make sure you cover the entire plant top to bottom side to side under over. After a day or two respray with just water to wash off the milk residue.
 
Rootsruler I read about that treatment a few different places. Lactobacillus makes antifungal enzymes. I heard it needs light to activate. People say it works well for outdoor plants, in the sunlight.
Hopefully I won't need to test it. My mildew problem has gone away since I tightened up my environmental conditions.
 
Bluey Depends on where you live. If you're in Cali then almond but if you're in the midwest, like Nebraska or Oklahoma then full fat or the cattle ranchers will have something to say! ;P
 
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