Powdery mildew late in flower

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Pearl

Pearl

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This grow has been hell compared to last year, but thanks to the help of @Aqua Man @GrowHobo with reveg guidance, and @Kopper1013 @strider26554 with borer guidance (piercing the stems was sheer genius), I've made it to this point! In addition to that, dealt with spider mites using persimilis a couple of weeks ago, but wound up having to partial harvest last week because of it :( The rest of that plant has to go this week.

And now..powdery mildew. Had to defoliate and remove some buds this morning unfortunately. The only thing I have on hand is Dr. Zymes, potassium bicarbonate, and over the counter hydrogen peroxide. Could either of those help with PM in flower? I have not sprayed anything but BT after week 1 of flower.

Close up pic is of the one I harvested. The one on the left in the other pic is the one just starting to show PM.
 
Powdery mildew late in flower
Powdery mildew late in flower 2
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GeoMcl81

GeoMcl81

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Oh no that's a bummer... I can't suggest clip off any leave with major coverage of mildew. My other suggestion would be spraying your plants with a pH of 5.5 water. The mold don't like the acid. It should get rid of keep from spreading.
 
Pearl

Pearl

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Oh no that's a bummer... I can't suggest clip off any leave with major coverage of mildew. My other suggestion would be spraying your plants with a pH of 5.5 water. The mold don't like the acid. It should get rid of keep from spreading.
Thank you! Defoliated a bunch. Hopefully keeps it somewhat at bay...will look into spraying with lower pH water.
 
L

Letsgrowit

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Use Dr Zymes on the PM. 4pz per gallon. I’d slake defoliate but those PM leaves go into a plastic bag and wipe down your hands. You can also use the potassium bicarbonate. May want to get some Lost Coast Plant therapy. Do 3 days straight of zymes. Then alternate every few days with lost coast and potassium bicarb. Then spot treat.
 
Pearl

Pearl

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Use Dr Zymes on the PM. 4pz per gallon. I’d slake defoliate but those PM leaves go into a plastic bag and wipe down your hands. You can also use the potassium bicarbonate. May want to get some Lost Coast Plant therapy. Do 3 days straight of zymes. Then alternate every few days with lost coast and potassium bicarb. Then spot treat.

This is super helpful. Thank you! Do you have a suggestion for the ratio of potassium bicarbonate to water?

I keep reading how using anything oil-based late in flower is a bad idea because it will affect taste/impossible to remove through budwashing. What do you think about that?
 
Pearl

Pearl

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Really anything in late flower isn’t good. Oil based especially. Try not to spray the nugs. And just the leaves

Ugh yeah. Such a tough call, but I feel like with 3-4 weeks left in flower, I have to do something. This plant is nowhere near harvest so even though it's only a couple of leaves right now, I know it can escalate quickly.

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Also, weather in NY this time of the year is so conducive to mildew and other fungal growth. Its incredible that last year, I had a plant that yielded over a pound without spraying anything the entire grow. This year is a completely different story.

Just sprayed with Zymes. Hoping for the best!
 
RootsRuler

RootsRuler

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I've never used it but have heard good things from trusted sources.

 
L

Letsgrowit

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This is super helpful. Thank you! Do you have a suggestion for the ratio of potassium bicarbonate to water?

I keep reading how using anything oil-based late in flower is a bad idea because it will affect taste/impossible to remove through budwashing. What do you think about that?
I don’t like spraying plants during flowering. But things like PM and caterpillars and botrytis must be addressed.

For PM during flowers, I only spray Dr Zymes on the flowers if needed. I would use Lost Coast if the problem was extensive or if Dr Zymes didn’t get it off. First thing is to defoliate.

I wouldn’t use potassium bicarbonate or potassium silicate on the flowers and would only spray leaves. I spot check daily for anything and address. I think it’s 1-2 tbsp for potassium bicarbonate. And less than 1/2 tap for silicate.

Lost Coast uses peppermint oil. Greencleaner uses sodium laurel sulfate. both use soybean oil and citric acid.

In terms if affecting flower taste, caterpillars, PM, and botrytis ruin the flower so we have to treat it.

You should also consider using Lactobacillus to fight PM. Things like Tribus and EM1 purportedly help as soil drenches and even foliar prevent it from forming.

BT for caterpillars.
 
Pearl

Pearl

51
18
I don’t like spraying plants during flowering. But things like PM and caterpillars and botrytis must be addressed.

For PM during flowers, I only spray Dr Zymes on the flowers if needed. I would use Lost Coast if the problem was extensive or if Dr Zymes didn’t get it off. First thing is to defoliate.

I wouldn’t use potassium bicarbonate or potassium silicate on the flowers and would only spray leaves. I spot check daily for anything and address. I think it’s 1-2 tbsp for potassium bicarbonate. And less than 1/2 tap for silicate.

Lost Coast uses peppermint oil. Greencleaner uses sodium laurel sulfate. both use soybean oil and citric acid.

In terms if affecting flower taste, caterpillars, PM, and botrytis ruin the flower so we have to treat it.

You should also consider using Lactobacillus to fight PM. Things like Tribus and EM1 purportedly help as soil drenches and even foliar prevent it from forming.

BT for caterpillars.

This is gold! I needed grounding because I'll admit, my mind is running in circles. I used silicate throughout veg so still have that on hand, and have been spraying BT every 5 days. I have EM5..not EM1 which I think is included in EM5...anyway, will look into EM1 and Tribus some more.

Going to use your post as my guide here on out. Thank you 🙏🙏🙏
 
L

Letsgrowit

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This is gold! I needed grounding because I'll admit, my mind is running in circles. I used silicate throughout veg so still have that on hand, and have been spraying BT every 5 days. I have EM5..not EM1 which I think is included in EM5...anyway, will look into EM1 and Tribus some more.

Going to use your post as my guide here on out. Thank you 🙏🙏🙏
I tried Tribus this year, and though expensive, appears to have had a positive impact. I recall the Lactobacillus Subtilus in Tribus that takes out PM. If you have budget, the brand Rootwise has some good microbes and bacterias.

For cats, PM, and budrot, I tend to be extreme and cut out the infected pieces.

I trust Dr Zymes just because everyone uses it. Regardless I will bud wash using the Cervantes method.

Also, next time I will use Regalia CG (knotweed extract) too but I read it can negatively impact the beauty of buds; however, I have heard good things about it reducing molds.

Finally “Athena mildew control” is supposedly helpful geranium extract. I do not think I would use regalia or mildew control at flower. Only in veg.

Good luck!
 
Pearl

Pearl

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I tried Tribus this year, and though expensive, appears to have had a positive impact. I recall the Lactobacillus Subtilus in Tribus that takes out PM. If you have budget, the brand Rootwise has some good microbes and bacterias.

For cats, PM, and budrot, I tend to be extreme and cut out the infected pieces.

I trust Dr Zymes just because everyone uses it. Regardless I will bud wash using the Cervantes method.

Also, next time I will use Regalia CG (knotweed extract) too but I read it can negatively impact the beauty of buds; however, I have heard good things about it reducing molds.

Finally “Athena mildew control” is supposedly helpful geranium extract. I do not think I would use regalia or mildew control at flower. Only in veg.

Good luck!

The amount of money I spent on this grow..💸💸💸 my goodness...it's embarassing to have any issues after throwing so much money at it.

It has been such a tough grow despite using premium products. I used buildasoil and coast of maine soil, rootwise products, silica, aloe vera, compost tea, amino from cod, peach extract..probably forgot some things. Meanwhile last year, I used only native garden soil and the grow was 99% uneventful. The native soil in my garden is premium from decades of composting and organic farming though so maybe it's my fault for overcomplicating it this year..but I digress. ALOT of lessons learned.

Truly appreciate the info you shared. Thank you again!
 
L

Letsgrowit

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LOL. I understand totally. I also use COM Stonington and Build a Soil. I used this year Craft Blend, Build a Flower, Big 6, Build a Bloom. I used Gnarly Barley twice. I ph down my water with Nectar of the Gods. I also use Rootwise and Tribus - and did the agsil as well as dr zymes, BT for cats, and lost coast. I should have done the regalia and will start BT in veg next year.

It’s coming out nicely fighting the tiniest amounts of PM (I literally will check them 2x a day). In fact going go out and shake them at midnight. Hope you get fire!
 
L

Letsgrowit

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Less is more I’m realizing. It costs me like $60 a run in nutes and sprays that yields 3+ lbs.

With that being said the pm would have probably have come regardless of any of those other factors. It’s more about the environment at the time. Make sure if you have any house plants near it or in your yard, to get rid of the pm on them too.
Yeah, I also spray the surrounding vegetation as you suggest, which is sage advice for sure. And try to control the canopy and airflow underneath. My overall lessons learned:

1) Do more LST and HST or else huge plants out of control
2) Consider IPM from day one - silica, regalia, dr zymes, lost coast. Else expect a larger than expected loss.
3) test your soil and adjust per plant.
4) ph the tap water always even in organic outdoors. This matters.
5) defoliate a lot more.
6) trellis and add supports
 
G

Glomus

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I'd consider a Cal/Mag supplement for next time if you aren't already using one, Cal/Mag with L-amino acids. Also bacterial inoculations can help. Buds look great!
 
Pearl

Pearl

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LOL. I understand totally. I also use COM Stonington and Build a Soil. I used this year Craft Blend, Build a Flower, Big 6, Build a Bloom. I used Gnarly Barley twice. I ph down my water with Nectar of the Gods. I also use Rootwise and Tribus - and did the agsil as well as dr zymes, BT for cats, and lost coast. I should have done the regalia and will start BT in veg next year.

It’s coming out nicely fighting the tiniest amounts of PM (I literally will check them 2x a day). In fact going go out and shake them at midnight. Hope you get fire!

Looks like we stimulated the economy the same way this year 🤣 In my case, it didn't work out exactly as planned..have to laugh otherwise will cry..

Yes! The midnight shake! I have neighbors directly behind my grow and I see their arlo cameras go off every time I check at night or early in the morning. At this point, I wave at the camera 😆
 
Pearl

Pearl

51
18
Less is more I’m realizing. It costs me like $60 a run in nutes and sprays that yields 3+ lbs.

With that being said the pm would have probably have come regardless of any of those other factors. It’s more about the environment at the time. Make sure if you have any house plants near it or in your yard, to get rid of the pm on them too.

THIS👍👍 I almost forgot to look into this. PM showed up on my cucumbers a couple of weeks ago. It wasn't spreading after spraying some potassium bicarbonate, and I was told that PM is plant specific so the PM on the cucumbers wouldn't affect the cannabis. I haven't had a chance to research that myself. THANK YOU for bringing this up.
 
strider26554

strider26554

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Glad to see that your grow is going to come cross the finish line, nice looking buds I might add. this year has been a non stop onslaught of really bizarre scenarios for me. last but not least of which I'm still dealing with is powdery mildew in flower. I have some thoughts on the topic that may or may not be of some benefit to you. First off, I don't believe that eradicating PM is even feasible without a complete chop, evacuate, sterilize and start over, and even then there's a chance you will miss the one spore that starts it all over again. That being said I will tell you what I have done, #1 NEVER spray anything on your buds. full stop. I don't grow this stuff to be dumping something i have no idea what's in on something that one of my loved ones rely on for their pain relief, that goes for baking soda, potassium bicarb, peroxide,,etc... , etc.,, it wont eradicate the pm anyway. The best way for me to approach this beast is to make the environment unsuitable for the invader, with light, air movement, and ph, and temp. Doing this outdoors can be a bit tricky when momma nature isnt having any of it. Here's what i found to be true also, PM has no rhyme or reason,, but it loves the dark little spots that dont get full sun or good airflow, use that to your advantage. defoliate with caution and remember to treat every plant completely and wash up before moving to the next, I use a plant mister to wet the leaves I may want to remove, the spores can become airborne during defoliating and you don't want that, and remember what your seeing on the leaves are the fruiting body of the mildew it means that the PM has been around long enough to mature and repopulate which means you have a systemic issue, now, I know the experts say that PM isnt systemic, but I say that it is and it isnt, its neither, what the mildew has done is to extend its feeding apertures which are little tendrils down into the leaf structures to pull the nutrients form your plant. which sounds pretty damn systemic to me. this also can be occurring on either the upper leaf or the underside, or both depending on which species or subspecies of pm that you are infected with. What i like to do is mist the plant until wet, remove all affected foliage, then very carefully inspect the stem, usually where the branches come from or the leaf stem is where you will often see a faint white or fuzzy spot, I clean all of these with a damp cloth. I have done some experiments this year that I normally wouldn't have done had I not been so damn near perfect with my new cloning technique. and the results are in, the plants I treated this way have done a little better, but some that I did not treat at all that were far enough away from my main grow areas as to not risk infecting them , did better. and it wasn't just one or two. Marijuana plants if healthy can tolerate PM and not affect overall plant health , bud size, or bud density. I have a couple of plants that have all the white spots on leaves and even on the stems, and look as though they are not bothered the least, they are vigorous, healthy almost mature with huge buds and no other problems save for the white spots and some yellowing that may or may not be related to the PM. so,, is this something that as growers we are all going to have to deal with forever? was this a particularly bad year for PM? or all of the above? If you look around in your yard, in the ditch beside the road leading to your house, and at the land upon which your abode is situated, do you see PM growing on anything else? My answer was, holy shyt! its everywhere, so unless you plan on changing into your sterile suit every time you visit your completely sealed and controlled environment grow room, you may experience this problem. And had better equip yourself with the few things we know work. There are some great resources for finding out more about the plant specific Pm that affects only cannabis's or the ones that affect all growing plants online, just google it. not to plug anyone specifically but mother earth news has some great articles about the topic.
 
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