Powdery mildew late in flower

  • Thread starter Pearl
  • Start date
  • Tagged users None
Pearl

Pearl

43
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

148
43
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.
 
F

FreeTheWeeds

29
13
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!
I used Coast of Maine for the first time in pots and also had issues. This after years of outdoors in the garden, with native soil, mostly augmented with cow manure added to the garden soil in the fall and turned again in the spring.

Next spring I'm starting with native soil and cow manure from the garden in the pots. I liked having the pots. Let me turn them a little daily so the plants were exposed on all sides for nice, rounded bushes.

Have a good day.
 
Pearl

Pearl

43
18
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.

@strider26554 the person who saved me from borer chaos! thanks for coming back to help again, and sorry to hear that you've had your share of difficulty this grow. Last year was so easy for me - I guess the universe thought that this year, it needed to be chaotic so I could gain some experience 😅

Your post has my gears turning, in a good way. I'm going to need a minute to think this through. First question - do you do any IPM during veg? Also, same question as @nashobaTHC - what are your thoughts on budwashing?
 
beluga

beluga

1,376
263
So I’m curious how do you feel about bud washing?
This is along my lines of thought.
It's commonplace to use h2o2 for harvest washes, especially for outdoor.
H2O2 is definitely effective against PM. I would try applications of that, personally.
It's probably too late for bacterial intervention and things like bicarbs or essential oils can and will ruin your flower.

Keep in mind some mildews are host-specific, some are not
Podosphaera macularis is the most common one to infect cannabis. Its other common hosts include: chamomile, strawberry, caneberry, and hops. Your cucumber or tomato PM will not necessarily take hold of cannabis, so a general treatment of adjacent plants may be in vain.

How is it today?
 
Pearl

Pearl

43
18
I used Coast of Maine for the first time in pots and also had issues. This after years of outdoors in the garden, with native soil, mostly augmented with cow manure added to the garden soil in the fall and turned again in the spring.

Next spring I'm starting with native soil and cow manure from the garden in the pots. I liked having the pots. Let me turn them a little daily so the plants were exposed on all sides for nice, rounded bushes.

Have a good day.

Agreed! The pots were awesome during veg. In addition to control over sun exposure like you mentioned, it made it so much easier to control watering. I tend to underwater, and the pots helped me dial that in.

That being said...the pot with Coast of Maine's Stonington blend (it's the one in the forefront in the picture below) started yellowing right before it hit flower even though the blend is supposed to have enough nutrients to sustain 120 days in a 20-gallon pot...


20220707 101655


After amending it, it turned green and is surprisingly healthy albeit just started yellowing again 😖 Could be normal...we'll see.:

20220919 181738


I wound up planting another pot in the ground in native soil because it started yellowing. It hasn't yellowed since! However, it's the one with PM....aside from that, it's doing really well.

The one in buildasoil 3.0 did well, except it had a pretty significant spider mite and thrips issue. I would use buildasoil again because the buds turned out incredible, as long as I can address the pest issue. I was advised to treat the soil before planting, but then I'd kill the beneficials too so I have to think that one through for next year.

In summary/TL;DR - Pots (during veg) and native soil for the win. My tomatoes love it. No cow manure, but that would be awesome. I use compost from my compost heap, and either Malibu or Coast of Maine compost when planting. Idk if I'll try Coast of Maine Stonington again.
 
L

Letsgrowit

38
18
This is some interesting content regarding h203 and other forms of bio controls.


My COM soil also yielded some yellowing leaves (and still is). COM stonington may be inconsistent in nutes. Same genetics, same treatment all season, bags from different stores have fed the plants differently. I don’t think it really lasts 120 days. I have one pot 60% fox farm and 40% stonington and do not have the yellowing issue.

Some say that in organics you want it to run dry of nutes and that yellowing later (weeks 5-8) is okay. I’m not sure, and am concerned adding pure n at 4 weeks into flower, especially a water soluble N so I have been top dressing build a bloom (2% soluble N 2-10-5).

That said I like the COM soil and would simply enrich it with BuildaSoil amendments. I would hit them harder with N in veg next time with COM.
 
Pearl

Pearl

43
18
This is some interesting content regarding h203 and other forms of bio controls.


My COM soil also yielded some yellowing leaves (and still is). COM stonington may be inconsistent in nutes. Same genetics, same treatment all season, bags from different stores have fed the plants differently. I don’t think it really lasts 120 days. I have one pot 60% fox farm and 40% stonington and do not have the yellowing issue.

Some say that in organics you want it to run dry of nutes and that yellowing later (weeks 5-8) is okay. I’m not sure, and am concerned adding pure n at 4 weeks into flower, especially a water soluble N so I have been top dressing build a bloom (2% soluble N 2-10-5).

That said I like the COM soil and would simply enrich it with BuildaSoil amendments. I would hit them harder with N in veg next time with COM.

Your experience makes me feel a little less crazy about the plant yellowing early. Mine happened in July - it was around 45 days. Super short. I contacted COM and they said simply to add nitrogen, so I used their "Buds and Bloom"/fish bone meal formula which did work. But it reappeared in August (Buds and Bloom worked again), and now again starting last week. I may go with build a bloom like you mentioned to see if the response is quicker than COM's buds and bloom...and simply because buildasoil's amendments haven't disappointed me yet.

Also, thank you for the info about the biocontrols. Some good reading material before bed tonight!
 
Pearl

Pearl

43
18
This is along my lines of thought.
It's commonplace to use h2o2 for harvest washes, especially for outdoor.
H2O2 is definitely effective against PM. I would try applications of that, personally.
It's probably too late for bacterial intervention and things like bicarbs or essential oils can and will ruin your flower.

Keep in mind some mildews are host-specific, some are not
Podosphaera macularis is the most common one to infect cannabis. Its other common hosts include: chamomile, strawberry, caneberry, and hops. Your cucumber or tomato PM will not necessarily take hold of cannabis, so a general treatment of adjacent plants may be in vain.

How is it today?

Just came in after inspecting and I'm kind of blown away because I only found two leaves with PM. Idk how that's possible.

Between Sunday and Monday, I carefully defoliated ~40 leaves as well as 4 branches with beautiful developing buds. The buds on those branches were covered in PM so they had to go. I did spray the leaves local to those branches with H202. I figured that hell, if it's good enough for Cervantes during budwash, I may as well...even though that makes no sense since he used it on harvested bud. Anyway. Yesterday evening, I sprayed with Dr. Zymes (4oz in a gallon), and plan on doing it again tonight and tomorrow. This is kinda miraculous, but don't want to get too excited yet.

It's almost impossible to not spray the buds at this point because there is a good amount of foliage and the PM is on leaves close to the buds. Would it be safe to spray with H202 considering that the buds will likely get sprayed? Maybe alternate with Dr. Zymes?

Also, godamnit about the chamomile. Here I am blaming the cucumber plants, meanwhile, I have chamomile growing within 5 feet that is long overdue for removal 🤦‍♀️
 
MendoCruz

MendoCruz

446
43
Athena IPM 1-2 times a week through veg to week 4 in flower and then switch to Dr. Zymes until the day before harvest. Both product work great as preventative and eradicator for mites and pm. You can use these without effecting look, flavor, or terpene percentages. We test between 3.5-5%
 
nashobaTHC

nashobaTHC

423
143
Regarding spraying to prevent PM I’ve used Purecrop1 twice so far at about 3 weeks into flower (after finding three leaves with PM that I pulled on 1 of 6 plants) and after 6 weeks in flower a day after plants dried out after heavy rains. So far no PM on any plants. 😅

However I did find minor bud rot on about 6 buds on only one plant (different from one with minor PM ) so those thumb sized buds were cut and tossed.

Today is windy but dry in NE Massachusetts after 2 days of rain and clouds. I also found a caterpillar near bud rot bud so I’ll be spraying all plants with BT this evening or tomorrow morning because I’m hoping to push plants another 2-3 weeks if possible.

Regarding bud washing in H2O2/water mix prior to drying, I’ll do that for budding branches that are less than 18” long but won’t on branches longer than that because they won’t fit into my wash container. I plan to hang large branches for slow dry and will inspect them and shake out “stuff” during dry trim process, which will require burning a fatty while listening to good tunes on noise reduction headphones. Keeping fingers crossed 🤞
 
2BEB28B8 6CD6 4601 9501 1402839249B4
B3DBE7BC 8908 4D8C 8CD0 2A1D44840C77
91603F93 EE2F 4A59 8AEC BCBFE99BDB45
8D6AB228 1631 4A85 A676 C3ED30D1333B
73FCD967 B6FB 40C6 B4DD ECFD2E421163
GNick55

GNick55

Staff
Supporter
5,571
313
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.
the strain of wpm that affects marijuana is not the same on any other plants..
 
GNick55

GNick55

Staff
Supporter
5,571
313
ok.. powdery mildew info is always being updated but still haven’t figured it out for cannabis and hemp..
85B3F4AC 9589 4BE7 B33D 7EFE86902058
 
Pearl

Pearl

43
18
Athena IPM 1-2 times a week through veg to week 4 in flower and then switch to Dr. Zymes until the day before harvest. Both product work great as preventative and eradicator for mites and pm. You can use these without effecting look, flavor, or terpene percentages. We test between 3.5-5%
Thank you! Another confidence boost that using Dr. Zymes was a good idea. That and the fact that the PM hasn't returned yet. Fingers crossed!
 
Pearl

Pearl

43
18
Regarding spraying to prevent PM I’ve used Purecrop1 twice so far at about 3 weeks into flower (after finding three leaves with PM that I pulled on 1 of 6 plants) and after 6 weeks in flower a day after plants dried out after heavy rains. So far no PM on any plants. 😅

However I did find minor bud rot on about 6 buds on only one plant (different from one with minor PM ) so those thumb sized buds were cut and tossed.

Today is windy but dry in NE Massachusetts after 2 days of rain and clouds. I also found a caterpillar near bud rot bud so I’ll be spraying all plants with BT this evening or tomorrow morning because I’m hoping to push plants another 2-3 weeks if possible.

Regarding bud washing in H2O2/water mix prior to drying, I’ll do that for budding branches that are less than 18” long but won’t on branches longer than that because they won’t fit into my wash container. I plan to hang large branches for slow dry and will inspect them and shake out “stuff” during dry trim process, which will require burning a fatty while listening to good tunes on noise reduction headphones. Keeping fingers crossed 🤞
First off - those ladies are pretty 😍 What strain are those?

PM hasn't returned after applying Dr. Zymes (and hopefully won't..). Really miraculous. But, budrot set in for my plants, too. Cut off a couple of buds. I was hoping to spray yesterday evening with BT, but it rained, was humid, and the temp dropped down to 50 from 75 degrees during the day...basically a hellish trifecta. Didn't spray today either because of high winds and it's going to be 50 again tonight...and I wrapped the supporting structure in a light frost protection fabric so I couldn't get to them anyway 😄

Speaking of the cold..how do you protect your plants?? I'm assuming they don't really need it at 50 degrees, but I was concerned last night that the significant temp drop would affect them.
 
Goodshit97

Goodshit97

263
93
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.
Im not trying to be "that guy" but didn't you post a thread recently about trying to achieve 2lbs in a 4x4, also being a newer grower? I might have it mixed up with someone else lol.
 
S

Slabby

89
18
Im not trying to be "that guy" but didn't you post a thread recently about trying to achieve 2lbs in a 4x4, also being a newer grower? I might have it mixed up with someone else lol.
Ya that was me. But if you saw the pics before I deleted them you saw the space is more then what that 4x4 title said. I pulled 3 lbs off a 4x8 on my first grow. Looking closer to 4 this time. Just wanted to see how I can improve, And Guarantee that weight. How’s that relevant though. What I said is true.
Unfortunately you are being that guy by insinuating that a new grower is somehow incapable of giving advice. Is anything i said in that post you quoted me on wrong or inaccurate? I don’t think so. So is this just a chance for you to feel superior over me or what? I’m confused.
 
Last edited:

Similar threads

H
Replies
5
Views
820
Ponky
Ponky
bunkerking
Replies
12
Views
1K
Dirtbag
Dirtbag
Ben1221
Replies
21
Views
969
Narsbars
Narsbars
Fro5ty
Replies
17
Views
634
TSD
TSD
Top Bottom