When to pull the pin on powdery mildew?

Hobbes

Well-Known Member
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Any pics?

I had PM on two of my last 4 plant harvest, I went to heroic efforts to save them. One is good for vaping after a bake to kill the PM, the other good for coconut oil.

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calvin.m16

Well-Known Member
I personally scrapped any tainted plants but first took clones. Treated the clones with Eagle20 @ 15ml gal. Vegged the plants for 2 months and had it tested nothing found in the flowers and the plants haven’t had mildew since. White Powdery Mildew is aids of weed plants. You have to use a systemic fungicide to cure them. Spraying all the organic overpriced stuff isn’t going to cure it only partially treat it.

eagle is extremely serious shit so don’t use it unless you know how to handle hazardous materials and sprays. Your best bet if you want to avoid fungicides or hardcore poison would be bleaching your grow and starting from seed.
 

xtsho

Well-Known Member
I started spraying with a potassium silicate solution which raises the pH. But either lowering or raising the pH to levels the PM can't exist in can help.

Methods that have been used to control PM for decades include both apple cider vinegar "acetic acid" and baking soda. One lowers the pH while the other raises it. I've found that the higher pH "alkaline" is safer to use as it's easier to cause burning with an acidic solution. But I'm spraying dozens of different kinds of plants in my yard some are more sensitive than others which is why I use an alkaline solution.
 

myke

Well-Known Member
29% h202 7 ml per litre. Will kill it and damage the area that’s sprayed. So if caught early u have a chance. Spraying a fungicide early in veg every week really is how to deal with it. As once you have it it’s a tough deal.
 

dark leaf

Well-Known Member
Ok, will post pics tomorrow. I moved one into a tent with a dehumidifier and the other three are still outside. Stripped them pretty bare to aid air flow. been using skim milk. Will try baking soda on some, potassium silicate on others.

Freaking RH here is 100% at night, 75% at best during during the day. The tent I keep it low, 30-50% day/night. The one in the tent seems worse though.
 

dark leaf

Well-Known Member
Ok I can't seem to find neem oil locally, might order some. Sprayed the 3 outdoor with baking soda and a couple drops of soap. Some pics of what I'm dealing with.IMG_7413.jpgIMG_7409.jpgIMG_7412.jpgIMG_7410.jpgIMG_7411.jpg
 

Khyber420

Well-Known Member
I personally scrapped any tainted plants but first took clones. Treated the clones with Eagle20 @ 15ml gal. Vegged the plants for 2 months and had it tested nothing found in the flowers and the plants haven’t had mildew since. White Powdery Mildew is aids of weed plants. You have to use a systemic fungicide to cure them. Spraying all the organic overpriced stuff isn’t going to cure it only partially treat it.

eagle is extremely serious shit so don’t use it unless you know how to handle hazardous materials and sprays. Your best bet if you want to avoid fungicides or hardcore poison would be bleaching your grow and starting from seed.
I have a meatbreath mother I want to save and regrow like this. Obviously I want zero eagle showing up in any clones' flower, how many clone/mother cycles does it take to completely get rid of a trace of eagle 20?
 

PJ Diaz

Well-Known Member
I personally scrapped any tainted plants but first took clones. Treated the clones with Eagle20 @ 15ml gal. Vegged the plants for 2 months and had it tested nothing found in the flowers and the plants haven’t had mildew since. White Powdery Mildew is aids of weed plants. You have to use a systemic fungicide to cure them. Spraying all the organic overpriced stuff isn’t going to cure it only partially treat it.

eagle is extremely serious shit so don’t use it unless you know how to handle hazardous materials and sprays. Your best bet if you want to avoid fungicides or hardcore poison would be bleaching your grow and starting from seed.
PM isn't systemic, that's a myth, look it up. If the disease isn't systemic, there's no requirement to use a systemic fungicide to cure the disease. Eagle 20 is nasty stuff to use on consumable crops. I'd suggest less drastic methods instead, beginning with environment, especially if your issue is popping up in veg.
 

PJ Diaz

Well-Known Member
reduce water, improve venting raise temps outta the teens to 20c, if really bad

neem oil applied 2x day if that bad...the taste will vape out long before harvest

good luck
Ok I can't seem to find neem oil locally, might order some. Sprayed the 3 outdoor with baking soda and a couple drops of soap. Some pics of what I'm dealing with.View attachment 4700029View attachment 4700030View attachment 4700031View attachment 4700032View attachment 4700033
IMO, neem is great while plants are still vegging, but would never spray that stuff past week 2 of flower. At this point the best bet is a H2O2 dilution. All that other stuff that's been suggested in the thread will leave a residue on your buds, while won't be nice to smoke.

 

PJ Diaz

Well-Known Member
I have a meatbreath mother I want to save and regrow like this. Obviously I want zero eagle showing up in any clones' flower, how many clone/mother cycles does it take to completely get rid of a trace of eagle 20?
The half life of Eagle 20 is 64 days. The half life is the amount of time it would take for half of the material to decay, so figure out how much you are gonna spray on the plant and do the math. Sounds like quite a long time to me. Systemics like Eagle 20 don't leave quick, which is why they work. Eagle 20 is made for golf courses, not for cannabis.
 

FastFreddi

Well-Known Member
Potassium bicarbonate....1 tablespoon per gallon of 10 ph water. Spray entire plant in low light.
Spot spray thereafter.
Works fantastic.
FF
 

Khyber420

Well-Known Member
The half life of Eagle 20 is 64 days. The half life is the amount of time it would take for half of the material to decay, so figure out how much you are gonna spray on the plant and do the math. Sounds like quite a long time to me. Systemics like Eagle 20 don't leave quick, which is why they work. Eagle 20 is made for golf courses, not for cannabis.
That's not the entire story, I wouldn't be sitting there waiting for it to dissappear. Steps:

1. Cure the mother
2. Clone
3. Grow the clone 3 ft
4. Take new clone from upper growth

Pretty sure if repeat this cycle 3 or 4 times the end result would have only minute traces. I'm just wondering how many cycles it would take.
 

PJ Diaz

Well-Known Member
If you have to spray the buds, you have already lost the battle.
Good luck.
FF
Agreed, but it's also often difficult to spray only the leaves without getting offspray on the flowers.
That's not the entire story, I wouldn't be sitting there waiting for it to dissappear. Steps:

1. Cure the mother
2. Clone
3. Grow the clone 3 ft
4. Take new clone from upper growth

Pretty sure if repeat this cycle 3 or 4 times the end result would have only minute traces. I'm just wondering how many cycles it would take.
PM isn't systemic, so you could just take a cut from the mother and use a different approach to cure it. PM is caused by environmental issues, so if you are getting PM, the first step should always be to get your environment in check. Airflow and humidity control goes a very long way in beating back PM. Also there are likely spores all over your grow area if you do have PM, so a good sulfur burn is likely needed to kill the spores hidden in the corners of the room.
 
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