89% Humidity After Lights Out Too High For Veg? Risk Of Mold?

[Trentski420]

Hi so I recent bought s humidifier went and checked it out after lights out and she was reading 89% and was fogged out.. I've noticed the raised humidity has done wonders for them could this be a danger in any way? It's only thus way at lights out and usually only gets as high as 60%-80%

 

[Savage Henry]

you may want to invest in a dehumidifier and put it on a timer to kick in when your lights are out.

Lights off spikes in rh can certainly lead to powdery mildew and other pathogens, especially if it's not a resistant strain.

 

[Trentski420]

??? Or I can turn my humidifier off......
And I got an AC with dehumidifier but avoiding that

 

[Savage Henry]

Oh yea, that should work just fine. A/c dehumidifies a fair amount without switching them the dehuey mode.

 

[Trentski420]

Ya that's original reason for getting humidifier but temps have dropped and no longer require the AC .. But seeing benefits from the humidifier I will never stop using one except flower (possibly still early flower)

 

[Trentski420]

So leaving humidifier on than either shutting off or putting in minimum (from maximum) should take care of spikes ?...

 

[Trentski420]

So I filled it up for the morning and shut it down.. Down to 80% RH at moment... What is your preferred optimal for veg (or more specifically pre-flower)

 

[Savage Henry]

I like to run 70% and around 80 degrees F, up through week 3 of flower then dial it back slowly until I'm @50% and 68-72f for the last couple weeks of flower. Look into vapor pressure deficit if you haven't already. Couple good threads on here regarding it.

I've let get higher, up to like 80-85% the first couple weeks of flower as well, with temps at 80-84, but that's after knowing the strain could handle it. And with co2 @ 800-1100ppms

 

[Trentski420]

Ok cool thanks

 

[Homesteader]

I am curious with the clear plastic. I cannot see the pic very well but I would be concerned with having it that close to an HID.

 

[Nog]

It can get really humid where I live, up into the nineties sometimes, but I don't have problems with mold.

Even at that humidity, as long as you have a fan blowing air on the buds all the time they don't mold.
With something like Critical Mass or some other huge budded plant things might be different, but with your average sized buds I have never had problems with mold as long as I have the fan blowing on them when the lights are off as well as on.

 

[We Solidarity]

unless you're growing in a shower I wouldn't encourage anything over 50% humidity. I've had the pleasure of cleaning up grow houses, 11 times out of 10 the inside of the walls are BLACK as in the drywall has had 1/4 inch eaten away by mold, and the floor joists and rafters are warped with signs of rot.

I wouldn't say you're too prone to PM unless you're getting a big temperature swing too, but botrytis is definitely a major concern. You can bet that with that high of humidity there is biological activity happening on pretty much every surface of your grow, and botrytis is a very very very common mold.

 

[Trentski420]

So many opinions some say 80% some say 50% ... That plastic sheet was only there for a minute because humidifier was causing condensation.. And it wasn't really closed to the HID at all considering its in a cool tube

 

[Trentski420]

Am I reading that wrong or does VPD directly relate to how quick/long my soil takes to dry out?

 

[Jasper Geist]

Bump. I was wondering the exact same thing with regards to soil. If it's too hot and it's arid then your plants will drink more water and the soil dries out.
Now if it's too hot and humidity is too high then will the plants transpire too much which then pulls more moisture from the soil? (I'm new to all this and I don't know compost!)

 

[Nog]

Running hot grow lights will lower your humidity.

The humidity can be in the 80's outside, but in the growroom it's 50 degrees humidity.

But that's with constantly venting the air out of the grow room, not with a closed grow room.
In a closed room without air extraction the moisture the plants transpire from the leaves into the air, plus moisture evaporating from the soil, will add to the moisture in the air raising the humidity.

"Bump. I was wondering the exact same thing with regards to soil. If it's too hot and it's arid then your plants will drink more water and the soil dries out. "

That's what you want; you want the soil to dry out as if the plants sit in wet soil for too long they will get overwatered.
You want them to go through a wet and then a drying cycle.
If they dry out too quick for your liking then use bigger pots.