My first dealing with the infamous white powdery mildew

etruthfx

Well-Known Member
I've tried this spray application before and had 0 results. I had negative pressure when I started in the room after I lined it with panda film, it was pulling the panda film inwards so I knew that I was at negative pressure but lo and behold PM began to develop. Heck I even took precautionary measures by spraying them with neem oil twice a week. So at that point I cut in a return grill assembly with a allergen filter and began using it as a fresh air intake. This pm seems to be producing at lights off.
I noticed a reduction in growth when I began turning off the humidifier during lights off. Last night I tried turning up the electric heater thinking that would help but it seemed worse. So I'm truly at a loss. These 5 plants that have PM are auto's that are 5wks in flower. One additional thing I tried last night 4 hrs before lights out was I sprayed only the affected leaves with neem oil and it didn't work. The balance of plants in the room shows no signs of PM.
The pm is showing up on random fan leaves and on sugar leaves near the buds but hasn't gotten on the buds "yet". I'm concerned about spraying anything near the bud sites because of my experience I had on my previous grow. I've spent lots of money and time I hate to forfeit it :cuss:
Use Plant Therapy or at last measure use eagle 20 it will take care of it trust I've done it before
 

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Bourbon 2

Well-Known Member
Use Plant Therapy or at last measure use eagle 20 it will take care of it trust I've done it before
I'll research it,ty.
So today I spent a good part of the day relocating the 5 infected auto's. I had tried most organic mixtures for foliar applications before and nothing worked so today I mixed up 2% milk and RO water in a sprayer and I saturated the plants, and now their milk drunk, lol. I have no fans on them, no humidifier and switching to 24/7. Fingers crossed this works :peace:
 

etruthfx

Well-Known Member
I'll research it,ty.
So today I spent a good part of the day relocating the 5 infected auto's. I had tried most organic mixtures for foliar applications before and nothing worked so today I mixed up 2% milk and RO water in a sprayer and I saturated the plants, and now their milk drunk, lol. I have no fans on them, no humidifier and switching to 24/7. Fingers crossed this works :peace:
What's the light schedule on now? Alot of times those house hold mix yourself organic solutions are only a temporary remedy not a permanent solution, it might hold it back but you want to knock it out completely. Definitely use a dehumidifier and fans, you might think that the spores will spread but use a treatment on them, stagnant air is going to make it populate more. Maybe spread your plants out away so the leaves aren't touching.
 

Bourbon 2

Well-Known Member
What's the light schedule on now? Alot of times those house hold mix yourself organic solutions are only a temporary remedy not a permanent solution, it might hold it back but you want to knock it out completely. Definitely use a dehumidifier and fans, you might think that the spores will spread but use a treatment on them, stagnant air is going to make it populate more. Maybe spread your plants out away so the leaves aren't touching.
25- 30% humidity w/o humidifier on, temperature average 72 degrees. No fans on now for the autos so the spores don't spread. In the grow room that I removed them from I added the exhaust and intake fans on the same timer schedule as lights on/off. And I removed the humidifier. The pots have plenty of spacing between them now.
 

etruthfx

Well-Known Member
25- 30% humidity w/o humidifier on, temperature average 72 degrees. No fans on now for the autos so the spores don't spread. In the grow room that I removed them from I added the exhaust and intake fans on the same timer schedule as lights on/off. And I removed the humidifier. The pots have plenty of spacing between them now.
You can spray with 71% iso alchohol if you have it on hand if you look its one of the ingredients of plant therapy
 

Justkickinit420

Active Member
Hello every one I'm the Brown Cow and I have been growing for 2 years now lol a little AA humor but ironically my first grow went rather well , I didn't get spider mites, I didn't get white powdery mildew and this was in a 4x4 tent with King LED lights purchased on Amazon . I only yielded like 4 ounces out of 6 plants under 1500 watt equivalent light but it went good . I grew in fox farms soil and used the trio pack and it worked , at the begging of this year I got two tents going and I had my first encounter with spider mites and used mitey wash and had to keep using it for almost the entire grow 12 plants but I got through it and yielded 10 ounces all together using 2 1500 watt King LED lights with some super cropping done . So I upgraded again and now have built a dedicated grow shed with a 4x8 flower room with a 6 inch inline fan bringing constant fresh air in and a 6 inch inline fan with a carbon filter blowing air out , 4 fans to circulate air in the room . I use a variety of nutrients now like big grow, big bloom , tiger bloom, pk booster, Koolbloom , monster bloom and am about to start adding overdrive. I dont use all the nutes together just so you guys have an idea of what I have used and Im growing in soil ,watering from a reservoir using drip lines and 3 600 watt hps light . So I have been upgrading each grow and to me I feel like it was all going good and I'm half way through the flowering stage when I notice some leaves with some white spots . I know from reading threads and watching youtube that its white powdery mildew and I have tried the milk solution , I have tried the peroxide solution and it didnt work so I bought some greencure hopefully it helps but I have two questions if anyone can answer please, question one all my Granddaddy purples have the white powdery mildew and the only two Girl scout cookies I have in the room right next the Granddaddy purples touching each other do not have the mildew on the plants why is that . question two I live in the high desert in California and I have a hard time getting my humidity levels up currently they are 25 percent and have never gone over 30 percent how did I get white powdery mildew the air is super dry up here . Any ways I hope it wasnt too much for my first post and any answer or even criticism will be greatly appreciated . Brown Cow out !
Powdery mildew is a spore that is airborne. There are many bandaids(sprays) that make the problem move and go away for a sec but that’s not the correct approach
Plants w high nitrogen content tend to be more susceptible to pm and contrary to popular belief lowering humidity only forces the pm to spread.
Sulfur is not the answer either.
Adjusting the ph of the leaf above 7 is a good approach but not the best.

Pm spores land on the plant and drop their tap root into the leafs cell wall and sucks the water outta the leaf and thrives. Soap will help kill it and raising the ph will also but once the spores drop tap and effect the plant if not in flower the clones will most likely be effected as well.
To prevent this keep you nitrogen levels in check but most importantly replace the water in the cell walls w pectin.
That’s right pectin.
To do that simply add amino acids to the res 1st then cal mag or A or what ever you use w calcium in it. The amino acids and calcium bond and your plant becomes very healthy once it’s full of pectin.
 
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Justkickinit420

Active Member
It took me 3 years of growing commercially until I did my resurch on how they beat powdery mildew in Europe after banning All fungicides on fruits and veggies.
Pectin
 
A lot of good info coming up as of late but are certain strains more prone to PM are certain strains more resistant to PM? I swear my Girl Scout cookies extreme strain that was in the same room not once showed any signs or symptoms of PM on the leaves and this Girl Scout cookies grows some huge fan leaves biggest I’ve ever seen . The Girl Scout cookies was literally touching plants with pm but would not contract it . On the other hand all the granddaddy purple sand the kush’s all had PM
 

Bourbon 2

Well-Known Member
A lot of good info coming up as of late but are certain strains more prone to PM are certain strains more resistant to PM? I swear my Girl Scout cookies extreme strain that was in the same room not once showed any signs or symptoms of PM on the leaves and this Girl Scout cookies grows some huge fan leaves biggest I’ve ever seen . The Girl Scout cookies was literally touching plants with pm but would not contract it . On the other hand all the granddaddy purple sand the kush’s all had PM
That's good info :peace:
 

Justkickinit420

Active Member
A lot of good info coming up as of late but are certain strains more prone to PM are certain strains more resistant to PM? I swear my Girl Scout cookies extreme strain that was in the same room not once showed any signs or symptoms of PM on the leaves and this Girl Scout cookies grows some huge fan leaves biggest I’ve ever seen . The Girl Scout cookies was literally touching plants with pm but would not contract it . On the other hand all the granddaddy purple sand the kush’s all had PM
Yes sir some strains will not get pm, spider mites will avoid some strains, gnats love some strains.
It’s not only strains but genotypes of strains
 
So I did what some other people did in their grow room after my harvest I disinfected my room with anything you can think of . I threw some strawberry cough strains , a Girl Scout cookies strains and some blueberry strains . The strawberry cough strain started showing early signs pm I defoliated a lot of leaves on the strawberry cough and used plant therapy and it’s been 3 weeks and no more signs of pm on the strawberry cough. But the Girl Scout cookies and the blueberry showed and are showing no signs . Crazy how plants are different .
 

Justkickinit420

Active Member
Update on the auto's. After relocating the autos and saturating them with the milk/water foliage application I'm happy to report that I see NO signs of PM :weed:
Try not to get your nitrogen levels to high plus the humidity swing in check once the lights go out.
These are 2 major contributors to the damn fungus.
 

Bourbon 2

Well-Known Member
Try not to get your nitrogen levels to high plus the humidity swing in check once the lights go out.
These are 2 major contributors to the damn fungus.
Yes, I got carried away with my hot soil. I use M3 soil and for this entire grow I added additional 2 cups of worm castings. Huge no no :(
My plants are healthy but showing nitrogen toxicity on some of the leaves on the underside of the canopy. So with that I've been watering with RO water to help flush. The auto's seems to be less affected by the added worm castings. Cheers :weed:
 

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curious2garden

Well-Known Mod
Staff member
Killing PM
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Based on my experience with Regalia I'd run Marrone Grandevo for Mites

Good luck
 
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