How To Use Uvc Light To Treat Powdery Mildew- Please Help!

  • Thread starter Greengrower8
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Greengrower8

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The problem is opinion vs fact. Liking Ford or Chevy is opinion or preference, not fact. The science of curing or treating PM should be based on facts not opinions. In my days and days of reading and researching, I have not read any experiences about Regalia or Procidic2 curing a case of PM. There is crap for days about how great it is as a preventative measure, etc, but I have read about zero experiences of anyone using either of these products on an outbreak of PM and curing it. I want to believe they work, but I would like to base my decision on facts, not opinion. And unfortunately, especially online, the line between opinion and fact can be practically nonexistent.
 
CaliRooted

CaliRooted

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Cool. I've said all I can for you. I don't grow for fun bro this is what I do full time and I do it well, follow my grow thread and watch experience speak for itself. You'll never get the answer online your looking for, sometimes you just have to make the leap! Good luck and Happy Growing!
 
CaliRooted

CaliRooted

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Last thing I will say is you are correct in your reading once you do have an issue these products are pushed to their limits but if it was me at week 3 I wouldn't fight it for 6 more weeks its honestly a battle you won't win. Preventative is key.
 
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Greengrower8

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Fighting it for over month is exactly what I’m trying to avoid. Clearly prevention is the key and next time I will absolutely be treating them with a few things, among doing other things, during veg so this does not happen again.
I got cocky, cuz the grow I did before this in the same space, using the same methods and equipment and there was not one spore of mold anywhere. I could have blown my nose with the leaves and been fine. Having this problem didn’t even dawn on me until it was too late.
Knowledge is key and I certainly appreciate everyone’s informative input here. I will probably end up getting either Regalia or Procidic2 - and if I do, I will certainly post my results so that others can benefit from my experience.
 
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Greengrower8

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I just remembered something I read a while back.

Will direct exposure to sunlight treat/kill/cure this PM? Like if I put them out in the sun for an hour or two will this help?

I remember reading something about using the sun (and it’s UV rays) and being able to eliminate bacteria, molds etc.

Obviously PM exists outside and is therefore exposed to sunlight so it’s clear PM can still proliferate while the sun is shining on it. Nevertheless, I remember reading about sunlight exposure killing bacteria, etc, especially on things that remain indoors and never get direct sunlight exposure.
 
SharkLasko

SharkLasko

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Without a pic, it's hard to say...however, that said, I thought I had the same thing (newbie here) and it was all over the top of my rockwool and on the bottom of the stem, turns out it was only dried salts from the nutrients. I hope you found out what it was before you killed the plant trying to save it. Please post a few pics, it will be way easier to diagnose. Good luck.
 
Jack og

Jack og

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Uvc light , 5min on every 8hrs , 3 days and get the air flow fixed, keep temp constant and humidity low as possible. It will sterilize the environment but u will need to spray something to finish pm off, sulfur is the best thing I’ve used, but the cleanup after is a mess. But it kills it in a day, repeat 3 days later and you should be done. I don’t have pm anymore. But I did fix my airflow. Its better to get it controlled before flowering begins.
 
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Greengrower8

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Well, apparently I have a small spider mite infestation also. This grow has been a frickin nightmare. I will NEVER use a minimalist approach again. I guess I just got lucky in the past. I will be treating them with as many things as possible from the start.

Picked up something called Green Cleaner from the hydro store today. It cost just as much as Regalia or Procidic2, but it treats PM and mites and I can get it a few ounces at a time so I don’t have to blow $100 to see if it works. Just soaked them up and down with it at 2oz/gallon. It did seem to literally wash the PM right off the leaves. Although, I’m much more concerned about these stupid mites, which seemed to appear out of nowhere overnight. Gonna reapply at 1oz/gallon in a couple days. I pray this works.
 
Jack og

Jack og

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Greencleaner works, but apply it often and check in between to see if the issues have subsided.
Just lights off when using this thing. The alcohol will leech the leaf fats. So lights off once applied for min of 8hrs.
 
hyzerflip

hyzerflip

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Like I said earlier, horticultural oil is fantastic. Not only is it effective against PM, it decimates spider mites too. It's cheap and is effective against virtually all cannabis pests and pathogens.
 
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Greengrower8

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After the initial drenching, things definitely look better. The PM especially- the spots that have been repeatedly popping up after being treated with H2o2 do not seem to be returning after Green cleaner drench.

The mites look better also, but they are far from totally eradicated. I still found some living upon close inspection. I will trim again and give them another soaking tonight. I realize that it takes several vigilante applications over a week or two to truly be effective.
In reading about spider mites, many people were talking about physically squishing them and watching them abandon the plant as it’s treated - I dunno wtf these people are talking about, cuz I can just barely see these things using my 10x loupe. They create a sort of thin cobweb, under and around the leaves. I don’t care what kind of mites they are - it seems they are all treated the same way. I just found those comments confusing.

Thanks for everyone’s ongoing help in dealing all this. You guys rock!
 
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sMo

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I can't answer the UVC light question, but my experience with PM is that it is incurable; being systemic, once contracted, that plant is permanently infected.

Nonetheless, you can keep a handle on it with a weekly spraying treatment of 2 tsp baking soda / gallon of water. It's very important to treat the entire plant. Also, as noted in many replies; Air Flow is crucial.

In veg, I spray weekly with a mixture of 2 tsp baking soda, 2 tbls Neem oil and 2 tbls Organocide 3-in-1 per gallon of H2O. Spray weekly regardless of the presence of PM, mites or other pests, molds....
I am NOT a fan of H2O2 in any strengths.
 
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sMo

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After the initial drenching, things definitely look better. The PM especially- the spots that have been repeatedly popping up after being treated with H2o2 do not seem to be returning after Green cleaner drench.

The mites look better also, but they are far from totally eradicated. I still found some living upon close inspection. I will trim again and give them another soaking tonight. I realize that it takes several vigilante applications over a week or two to truly be effective.
In reading about spider mites, many people were talking about physically squishing them and watching them abandon the plant as it’s treated - I dunno wtf these people are talking about, cuz I can just barely see these things using my 10x loupe. They create a sort of thin cobweb, under and around the leaves. I don’t care what kind of mites they are - it seems they are all treated the same way. I just found those comments confusing.

Thanks for everyone’s ongoing help in dealing all this. You guys rock!
The trick with spider mites and herbal oils, (Neem, Greencleaner, etc.), is direct contact. It works by suffocating the mites. they do not have lungs, they breath when they walk by pumping air thru slits in their backs. block the slits and they die.
 
45North

45North

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93
UV-C will destroy the plant. It works best to clean grow area between crops,
45n
 
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sMo

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... I got cocky, cuz the grow I did before this in the same space, using the same methods and equipment and there was not one spore of mold anywhere. I could have blown my nose with the leaves and been fine. Having this problem didn’t even dawn on me until it was too late...
Haha, yep, I think every grower gets cocky at some point, (I did), then we get a slice of humble pie. I've known a number of growers, large and small grows, and shit happens to everyone occasionally. It's normal to have 2-4 great grows, and then some unforeseen issue happens.
Some growers just dump a difficult crop but I never do. You'll learn more by finishing a crop then starting a new one.
 
Jrmy911

Jrmy911

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Watched some vids by Cornell and they found PM cures itself during day but at night turns off healing processes to repair UV damage and that's when they are suseptible. Many videos of commercial grows using UV light to fight fungus.....like previously stated concentration and time are what is needed to understand how to treat.
 
LedGuy

LedGuy

21
3
Watched some vids by Cornell and they found PM cures itself during day but at night turns off healing processes to repair UV damage and that's when they are suseptible. Many videos of commercial grows using UV light to fight fungus.....like previously stated concentration and time are what is needed to understand how to treat.
Do you have links?
 
PileatedSmkr

PileatedSmkr

2
1
Hey All,

Hope you don't mind me re-opening this post. We are new to growing, about 4 wks into flowering of first crop, actually. PM has been an issue from almost the beginning; its a shop grow and has been a very humid summer (a few modifications are in the works for environmental improvement). Apparently, we are not the only ones fighting the problem. I started spraying with a mixture of Hydrogen Peroxide and Enzyme Komplete. Regularly; and it had little to no effect. The temperatures were good, but the humidity levels uncontrollable. And, like someone mentioned, the plants in front of the fans were as bad or worse than the others! I came across UVC lights for a/c ducts and installed it into a short tin box with an 18" box fan blowing air past the light, towards the plants. Its been on for about a week, and there appears to be an incredible improvement. I'm just not sure about the damage; that newbie thing :( . I've been running it 24/7, but diverting the glow during the night. We're also running with a mix of HS and LED's, just to make everything more interesting.

So, long story short, I'm still interested in ideas, reviews, solutions for UVC lights and PM eradication.
 
Joshsmokey

Joshsmokey

15
13
The 4th and 5th reply in that post discuss the science of using UVC light to kill PM.
I know it’s dangerous. I thought it may be more commonly used than I am finding, but everyone is just scared to death of it. There are plenty of articles supporting these type of lights to sanitize in horticulture, but it doesn’t seem like anyone messes with them.
So according to google uvc light on cannabis u just run the light over the plant no more than 3 seconds daily for about three days u will see a difference any more then 5 seconds will kill the dna if ur doing a small grow tent I suggest getting an Amazon wand uvc they aren’t as high as the expensive ones so they are lil safer (ON PLANTS ONLY ) it is irradiation so do not let touch skin wear long sleeves with thick gloves and eye protection it is nasty stuff to ur body I have a wand coming I. An done quite a bit of reading on this and seems to be great if done in short periods
 

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