Annoying powdery mildew

[skoomaman]

Seeing this stuff is quite disappointing. I noticed it about a week ago on my outdoor plants. First thing I did was remove a bunch of lower branches and infected leaves then wipe down each leaf with a cloth soaked in peroxide then spray the plant with a 1:4 peroxide to water solution.
The PM started appearing a few days later but not as bad.
This time I tried spraying some compost tea, thinking the bacteria would stop the mildew, it helped a bit but it keeps coming back. since then I'm simply pulling infected leaves off and disposing of them far away.

What can I do next? I'm not sure if I should just keep pulling leaves off or spray something stronger. The buds are forming nicely and I would love not to have to spray any chems on there.
From reading about PM, seems like I could spray with peroxide or baking soda solution.

Any help on the subject would be appreciated.

link of high res pic

 

[pute]

PM in flower. Wow! I know what I would do. Good luck in your battle but it gets in the buds themsleves. I have used safer fungicide and it works pretty well. You can also do a sulphur burn. Peroxide helps as well. I have successfully fought it back in veg but flower is another thing. If you do find it inside the buds at harvest try a green cure bath. But, you and whoever is still inhaling it into your lungs. I won't smoke it, nor will I let my friends.

Personally, I would burn it down and start over. Bomb the room and wash it thoroughly with concentrated (33%) peroxide. You also need to think about what caused it in the first place and keep it from happening again.

Good luck.

 

[skoomaman]

oh man, not good news. I don't think I can burn the plants. It isn't super bad yet.

Since I posted this, I have removed a whole bunch of lower branches and as many infected leaves as I could spot as well as a lot of large overlapping fan leaves. I will spray with a peroxide solution in a few mins.

Would it be a good idea to get some Potassium bicarbonate to spray with?

I definitely need to figure out how it happened in the first place.
Everything was going fine in veg.
This is an outdoor grow done in a diy green house.

1.) I did not prune enough
2.) lack of airflow due to not pruning
3.) something else I noticed today. See Pic
I noticed a tree that is about 10 ft away from the plants is covered in the mildew stuff. could the spores have come from that tree?



Here are some pictures of the greenhouse and plants. The left side wall is not normally on, we had a storm with high winds last night.

 

[pute]

I have been told that is a different kind of PM. I don't know though. As far as treatment I gave you my best stuff. Somebody else that has had more experience with it might help.
Check the small sugar leaves at the base of the bud. Cause if it is in the bud, which I think it is or will be, it will show up there. So sorry!
I have had it twice both from cuts on and outdoor grow. That crap thrives in a tent. I know people on outdoor grows that don't really worry about it. You might be ok. How long till harvest?

 

[skoomaman]

So far only some of the sugar leaves have been affected, removed those ones. Its mostly on the fan leaves, removed a lot of those today.

I'm gonna fight it off as long as possible. Some parts of the plant are completely fine while some colas were infested. I removed as many infected leaves as possible. Now its spray time, will try peroxide again today. Ill get some fungicide tomorrow.

TBH I'm not sure how long still. maybe 2 - 3 weeks?

high res Bud pic

 

[pute]

Some strains will be infected and some won't. If it's in your sugar leaves it's in your buds. How long till harvest?

 

[pute]

By the way, PM is like herpes! You can contain but will always be there. I use OG Bio War to help prevent it. There are may ways to prevent it. Do some investigation.

 

[stain]

Still cool humid air is the problem I've found. Put a fan on the plants.

 

[WeedHopper]

I have have never grown weed inside without fans moving air and moving my plants. Keeps BR amd PM at bay and makes the stalks big and strong.

 

[TheSadBadGrower]

Pm is such a problem for basement growers....not sure if this is you. If it were me, I would scrap the entire grow...clean and start over....but that's me. Environment is such a vital role in growing and sadly one of the most overlooked parts of a grow.

 

[Mike143]

Never spray baking soda on buds.The mix is to alkaline and will scorch them badly.Lol,Found that out the hard way.Trim it out I mean go into it and remove All the large fan leaves.You want to make as much air flow around them as you can.You will not hurt these big beauties doing that and will possibly increase yield.They won't look as impressive after you are done but they will recover.Get that other plant that is infected outta there as well.Now!Spray peroxide mixture every three days for about a week or two,keep an eye out for the mildew,when you stop seeing mildew stop spraying,when spraying saturate everything,top bottom of leaves, stems are also very important,and spray the soil,to kill any spores on that as well.The advice of fans are also very good,if that is not possible maybe you can remove a side to increase air flow.The key here is increase airflow,and butcher it a bit,by the time you are done the only thing you want on the plants is the sugar leaves and afew smaller leaves,you want to increase air flow around the buds,and treat the area around the other plant as well.Do this and you should be good,but keep an eye on the buds,any with mildew trim them out,I'd rather lose a few buds as opposed to the whole plant. Good Luck,

 

[skoomaman]

Pm is such a problem for basement growers....not sure if this is you. If it were me, I would scrap the entire grow...clean and start over....but that's me. Environment is such a vital role in growing and sadly one of the most overlooked parts of a grow.

Its an outdoor grow, kind of my only option. I built the greenhouse to have a way of protecting them quickly when a storm comes in. (got a huge storm come through a while ago that snapped some branches.)

Never spray baking soda on buds.The mix is to alkaline and will scorch them badly.Lol,Found that out the hard way.Trim it out I mean go into it and remove All the large fan leaves.You want to make as much air flow around them as you can.You will not hurt these big beauties doing that and will possibly increase yield.They won't look as impressive after you are done but they will recover.Get that other plant that is infected outta there as well.Now!Spray peroxide mixture every three days for about a week or two,keep an eye out for the mildew,when you stop seeing mildew stop spraying,when spraying saturate everything,top bottom of leaves, stems are also very important,and spray the soil,to kill any spores on that as well.The advice of fans are also very good,if that is not possible maybe you can remove a side to increase air flow.The key here is increase airflow,and butcher it a bit,by the time you are done the only thing you want on the plants is the sugar leaves and afew smaller leaves,you want to increase air flow around the buds,and treat the area around the other plant as well.Do this and you should be good,but keep an eye on the buds,any with mildew trim them out,I'd rather lose a few buds as opposed to the whole plant. Good Luck,

Damn, thanks for the heads up. I have a ph meter, what if I check before spraying?
I stripped it down today and the above pictures are after doing that.
Is removing ALL the fan leaves ok? I was thinking about this but wasn't sure how far to go.


about the fans. I'm outside, daytime is usually windy, would it help to keep a fan on them at night when its humid and calm?

 

[Mike143]

You can ph a baking soda mix,I guess,but I would just skip using baking soda this far into bud.I have read alot of good things from people using a vinegar mixture but I personally have only used peroxide in flower,except for the one time I burn't my plants with baking soda.As for trimming, yes remove everything that will block light from your buds and open the plant up.When you are done,they should look like stalks with buds on them.

 

[pute]

Thanks for the input Mike. I hope I never have to use it.

 

[skoomaman]

Ill skip the baking soda, lol. thanks
vinegar seems like it would work, a milk solution has appeared more often however from what ive read today.

Are you sure about removing all the fan leaves? I buy it, seems like the infection starts there. It just seems so dramatic, doesn't the plant need some fan leaves?

I don't mind spraying peroxide on it if it keeps the PM at bay and allows to keep the fan leaves. (if its worth the risk)

 

[Mike143]

Your plant is heading into it's twilight,it no longer needs the fan leaves,and will start to cannabilize them,that is why fan leaves start turning yellow on healthy plants already budding.The sugar leaves are what is feeding your buds,also the fans are helping to spread your mold.I completely strip mine after budding and after about two weeks I have to repeat this again where new leaves have grown out.If you want to save these plants you must take drastic action

 

[user 60570]

Oxidate right up to day before harvest

 

[ROSTERMAN]

Thanks for the input Mike. I hope I never have to use it.

Pute
What do you think About GreenCure
I have used it in the past every week through flower,

Now I wonder

https://www.biconet.com/disease/greenCure.html

 

[pute]

I only used it once and it was 10 years ago. Tried to salvage by giving a green cure bath at harvest. Did seem to mitigate the obvious pm but was still inside the bud when you crack it open. Many would probably go ahead and smoke it or even make hash or kief but I threw it it the trash. When you get old you shouldn't be sucking that into your lungs. IMO.

I am in a high desert and usually very low humidity. I fight to keep it over 40% in winter and have great ventilation so I have only had PM twice and both times it came from another grow via clones. So, pm is an after thought for me.

 

[WeedHopper]

Mold shouldn't be a problem if your making an alcohol extracted oil.