65% rh flower

orangeade5

Well-Known Member
I run 50-65% all the way through flower, I do believe in vpd. That being said I have overkill exhaust and a dehumidifier that keeps everything in the area in check. I guess it's also notable that I live in a dry climate but I love it and haven't had mold in years.

FRESH air is the enemy of mold.
 

davillains

Well-Known Member
I run co2 now but dare not go VPD through flower ... would love to hear from more people who are successful with it cause it has been bugging me...
 

MichiganMedGrower

Well-Known Member
Greenhouses use the vpd chart to help mitigate issues in the hot humid environment they inherently have.

But indoors we have much more control. I see healthy vigorous mold free plants at 75 degrees and 50% humidity. And the breeder of my genetics grows in the same environment so I assume that is a big factor.

The only moldy bud I have seen in my room was in the summer while I struggled to stay under 65% humidity.
 

Budley Doright

Well-Known Member
Are you guys talking about actual mould or PM? I grow outdoors in the summer and humidity is 85-90% with temps in the high 80's. Some of the auto's I have ran are prone to PM but the photo's never have an issue until late in flowering when rot can happen. Being RH is not a true indicator of the actual moisture in the air but the amount at that particular temp I would think VPD would be a great tool. I actually keep my humidity low but it can creep up to 65 and have never had issues inside, it's a photo only zone as well lol.
 

MichiganMedGrower

Well-Known Member
Are you guys talking about actual mould or PM? I grow outdoors in the summer and humidity is 85-90% with temps in the high 80's. Some of the auto's I have ran are prone to PM but the photo's never have an issue until late in flowering when rot can happen. Being RH is not a true indicator of the actual moisture in the air but the amount at that particular temp I would think VPD would be a great tool. I actually keep my humidity low but it can creep up to 65 and have never had issues inside, it's a photo only zone as well lol.
Interesting you mention that RH Is not accurate for actual moisture. I wonder if that is why it seems that every guide and article says to keep the RH around or below 50%? Keeps things in a safe range I guess.

I only grow indoors in ventilated growrooms so far.

And my comment about vpd and greenhouses sure applies to your outside grow. But I don't think my plants would like 90 degrees and 80% + RH under the lights. It's like a target for pests and bacteria is what I would fear.
 

Budley Doright

Well-Known Member
RH is dependant on temp so that's why I question the blanket statement of 50% or whatever, that is why I would think VPD would be a good tool and also you can apply that to midday depression as well.
 

Shugglet

Well-Known Member
It would seem VPD is most beneficial when running co2, are you? Also, Id be surprised if half the people commenting in here even know how VPD functions, just regurgitating the old tried and true info.

That being said, generally the tried and true method is the way go for most considering PM/mold can quickly decimate your crop.
 

a mongo frog

Well-Known Member
Also, Id be surprised if half the people commenting in here even know how VPD functions
What should happen then? Honestly everyone knows what VPD is and how it operates. Its basic gardening when enriching. Its like in the first sentence. Wouzer said it when he flipper over fillper truster. You know that.
 
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