Could I run a heater in my tent for a while and sterilize powdery mildew that way?

Powdery mildew showed up on this run about 4 weeks into flower and I can’t get rid of it. I am about to toss the plants and restart so I am wondering if I could just crank a few space heaters in my tent for a few days to kill any spores.

I’d like to avoid spraying everything down with chemicals and such and cleaning fan blades and grills and cords etc. as far as I know, powdery mildew is my only contaminant and I heard heat will kill it.

From what I’ve read, you need100 degrees F for several hours, so it could work. Me personally, I’d follow up with a chlorine solution or isopropyl alcohol spray. (Note: isopropyl alcohol is flammable, so turn all electrical device off until it’s evaporated). The problem with pm and most other fungal/mold spores is they are floating in the air, on you, on your clothes, so you will end up with them, but it will certainly cut down the numbers.

Perhaps. If you google "temperature needed to kill powdery mildew" you'll get a variety of answers. You might be able to get the tent up to that temperatue but your wallet might give out first.

Another approach might be to look up ways to prevent PM. PM is a well know and well researched issue in the agricultural science world. That's where I'd look for information on best practices.

One tip that I will pass along that comes from both the ag world and the research world is that using a silica supplement will dramatically reduce the likelihood of getting fungus or mold. It's very inexpensive and can save a world of hurt.

Delps8 said:

Perhaps. If you google "temperature needed to kill powdery mildew" you'll get a variety of answers. You might be able to get the tent up to that temperatue but your wallet might give out first.

Another approach might be to look up ways to prevent PM. PM is a well know and well researched issue in the agricultural science world. That's where I'd look for information on best practices.

One tip that I will pass along that comes from both the ag world and the research world is that using a silica supplement will dramatically reduce the likelihood of getting fungus or mold. It's very inexpensive and can save a world of hurt.

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I actually did just that and the spread seemed to be 90-100 degrees for a few hours, I went with the higher temp. It shouldn’t be too expensive for only a few hours. Yes silica will help. I add DE to my soil when I amend it. DE takes a while to break down, so it cooks until I need it. Silica supplements are available to the plant much quicker.

I've read something about wpm spores just waiting to grow, I'd go with isopropyl alcohol, bleach solution or H202, I'd research which of those was most effective against wpm.

How big is the tent? A small dehumidifier and fans would be more than enough to keep the PM at bay.

Ive treated PM with baking soda water. Its effective as long as you control humidity and air flow.

Is your tent located in a basement? Or in a space that is always damp and cool? If so, you will need to make a few more simple adjustments to get your grow back on track.

Delps8 said:

Perhaps. If you google "temperature needed to kill powdery mildew" you'll get a variety of answers. You might be able to get the tent up to that temperatue but your wallet might give out first.

Another approach might be to look up ways to prevent PM. PM is a well know and well researched issue in the agricultural science world. That's where I'd look for information on best practices.

One tip that I will pass along that comes from both the ag world and the research world is that using a silica supplement will dramatically reduce the likelihood of getting fungus or mold. It's very inexpensive and can save a world of hurt.

Click to expand...

Any recommendations for a product? Will a silica supplement help with the plants that are currently having PM on their leaves? I have an assembly line type of grow system, seedling tent, veg tent, flower tent, and was planning on tossing and cleaning all. But if I could use this supplement once they are in flower that would be nice because the PM doesn’t show up until mid flower.

Farmer's Hat said:

How big is the tent? A small dehumidifier and fans would be more than enough to keep the PM at bay.

Ive treated PM with baking soda water. Its effective as long as you control humidity and air flow.

Is your tent located in a basement? Or in a space that is always damp and cool? If so, you will need to make a few more simple adjustments to get your grow back on track.

Click to expand...

im in a 4x4 tent and its under 50% RH all the time during flower. I have 4 6” fans in my tent, I keep my exhaust fan running on high 24/7, so I do t know why I have this OM. However, I do have a 10F temp swing every time the lights turn on or off, and I’ve read that temp swings can cause PM.

Edit: I am in a basement, it’s about 60F in my basement, lights on temp is around 78f and lights out is about 68f.

I have to run a space heater to keep it at that temp, other wise the swing is like 20f and my humidity will go up with the lights out.

dopenixon said:

im in a 4x4 tent and its under 50% RH all the time during flower. I have 4 6” fans in my tent, I keep my exhaust fan running on high 24/7, so I do t know why I have this OM. However, I do have a 10F temp swing every time the lights turn on or off, and I’ve read that temp swings can cause PM.

Edit: I am in a basement, it’s about 60F in my basement, lights on temp is around 78f and lights out is about 68f.

I have to run a space heater to keep it at that temp, other wise the swing is like 20f and my humidity will go up with the lights out.

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Ive noticed that this is a common issue. Basements tend to be humid. That humid air goes into the tent and thats where the mold spores are coming from.
One option is to run a dehumidifier in the basement, keeping rh around 40-50.
The other option is to build a lung room for your tent.

dopenixon said:

Any recommendations for a product? Will a silica supplement help with the plants that are currently having PM on their leaves? I have an assembly line type of grow system, seedling tent, veg tent, flower tent, and was planning on tossing and cleaning all. But if I could use this supplement once they are in flower that would be nice because the PM doesn’t show up until mid flower.

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I used Botanicare's bottled nutes for my first few grows so I used their SilicaBlast product. I switched to using raw Potassium Silicate and mixing my own to get to the % of silica in SuperThrive Protekt. It was easy to do - just mix in the silica into warm water and heat util the boiling point - but Protekt is so cheap, I can't say that it's worth the bother.

Found the instructions. Attached.

Also attached is a PDF by Dr. Bruce Bugbee re. reservoir management. Check his CV on the web. It's detailed but the highlighted sections were my takeaways.


Re. "Will a silica supplement help with the plants that are currently having PM on their leaves?" No. It's prophylactic. I'm not familiar with how to deal with PM once it hits.

Add the silica mix to your nutrient mix. It must be added first or it will precipitate out of solution. It will precipitate if your nute bucket isn't clean, too. Picky bugger but it does the trick.

I use it throughout the grow even though, I think it's in the Bugbee paper that I attached that it isn't taken up as plants get older. I guess I should look into that, though.

Farmer's Hat said:

Ive noticed that this is a common issue. Basements tend to be humid. That humid air goes into the tent and thats where the mold spores are coming from.
One option is to run a dehumidifier in the basement, keeping rh around 40-50.
The other option is to build a lung room for your tent.

Click to expand...

Dehu is a "must have" unless you live in a desert.

My grow is in an unheated garage in Southern California. I'm only 12 miles from the ocean so RH ranges from 80 to about 40. I start up a large Waykar dehu when I start a grow because it's easier to put a humidifier in a tent and add a few % than it is to get RH down.

In fact, I run a dehu in the tent, as well. I dump the tank on that little dehu every AM and pour out 150-250ml (my grow is in mid-flower now with VPD at 1.3).

Having lost a beautiful plant to bud rot, I take no chances.

Delps8 said:

Dehu is a "must have" unless you live in a desert.

My grow is in an unheated garage in Southern California. I'm only 12 miles from the ocean so RH ranges from 80 to about 40. I start up a large Waykar dehu when I start a grow because it's easier to put a humidifier in a tent and add a few % than it is to get RH down.

In fact, I run a dehu in the tent, as well. I dump the tank on that little dehu every AM and pour out 150-250ml (my grow is in mid-flower now with VPD at 1.3).

Having lost a beautiful plant to bud rot, I take no chances.

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Indeed. One of the best investments, a dehumidifier.

I ran an ozone generator with all my fans, ac, dehumidifier going. Never had it again

Delps8 said:

Dehu is a "must have" unless you live in a desert.

My grow is in an unheated garage in Southern California. I'm only 12 miles from the ocean so RH ranges from 80 to about 40. I start up a large Waykar dehu when I start a grow because it's easier to put a humidifier in a tent and add a few % than it is to get RH down.

In fact, I run a dehu in the tent, as well. I dump the tank on that little dehu every AM and pour out 150-250ml (my grow is in mid-flower now with VPD at 1.3).

Having lost a beautiful plant to bud rot, I take no chances.

Click to expand...

Okay I have a dehumidifier

Gemtree said:

I ran an ozone generator with all my fans, ac, dehumidifier going. Never had it again

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i vent my fan outdoors because I felt like I was having an allergic reaction to the exhaust, maybe the charcoal, so I wonder if I could do the same.

I've been kicking around the idea of running a UVC bulb in the drying tent....not constantly, but intermittently....just as a preventative to powdery mildew from developing.

tstick said:

I've been kicking around the idea of running a UVC bulb in the drying tent....not constantly, but intermittently....just as a preventative to powdery mildew from developing.

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The downside of UV light is that it degrades THC rather quickly, at about 0.5% an hour!

Phytoplankton said:

The downside of UV light is that it degrades THC rather quickly, at about 0.5% an hour!

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Yeah I’ve heard that. I want to scrap my plants though and sterilize an empty tent to make sure the spores are dead.

dopenixon said:

Powdery mildew showed up on this run about 4 weeks into flower and I can’t get rid of it. I am about to toss the plants and restart so I am wondering if I could just crank a few space heaters in my tent for a few days to kill any spores.

I’d like to avoid spraying everything down with chemicals and such and cleaning fan blades and grills and cords etc. as far as I know, powdery mildew is my only contaminant and I heard heat will kill it.

Click to expand...

get an ozone generator... TRUST ME.

I bought an ozone generator a while back they're only a fraction of what I remember, I remember they cost circa £200 now for a 20k mg/hr they're only £25±
Before a crop I give a blast of ozone, fyi ozone is bad news in or around plants or bud it's a known terp killer.

I'll 4th or 5th the ozone generator. Easiest, and best way of doing it. I got mine a couple years back and super happy I did. Bonus, when you go out to work you can run it in your kitchen or living room to freshen up the house. Just make sure it has a good few hours to degrade back to oxygen, and give it a quick windows open for a few mins so it's not harmful to inhale.
Doctor zymes, bleach, peroxide, hypochlorous acid, are all good cleaners and also will kill spores etc. good for a secondary 'make sure' on top of the ozone
Make sure to clean all little cracks and crevices, especially anything made with cloth material.....