Highest humidity you have had during flowering without problems

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chronnie49

Well-Known Member
I have 2 blue kush and 2 gorilla that are 6 weeks into flower and I'm wondering the higest humidity you have had during flower.

With lights on my humidity is mid to high 40s and 75 temp, lights off the humidity rises to high 60s and temps 64-68. I have an 8 inch exhaust fan, 12 inch oscillating fan blowing between the lights and canopy and a 9 inch fan on the floor blowing under the scrog net. I have a dehumidifier which lowers the lights off humidity to mid to high 50s but it uses 500 watts so trying to save a little money by not using it but dont want to risk mold or budrot.

Would you guys be worried with humidity in the high 60s when lights are off even with good air flow?
 
StareCase

StareCase

Well-Known Member
Your 8" exhaust fan and the 2 circulation fans should keep humidity low enough and air movement high enough to prevent mold and mildew during lights off. I use a 4" exhaust @ 75% speed continually sucking in clean 35% humidity air with three small 6" circulation fans mixing it all up in the tent. They are are running 7/24.

What speed is your exhaust fan running during lights off?
 
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chronnie49

Well-Known Member
The exust fan is on a voltage stepping controller running at around 300 cfm in a 5x5x7 tent.

I live in a humid country so the humidity in the room the tent is in is 50-65 percent.
 
thumper60

thumper60

Well-Known Member
chronnie49 said:
I have 2 blue kush and 2 gorilla that are 6 weeks into flower and I'm wondering the higest humidity you have had during flower.

With lights on my humidity is mid to high 40s and 75 temp, lights off the humidity rises to high 60s and temps 64-68. I have an 8 inch exhaust fan, 12 inch oscillating fan blowing between the lights and canopy and a 9 inch fan on the floor blowing under the scrog net. I have a dehumidifier which lowers the lights off humidity to mid to high 50s but it uses 500 watts so trying to save a little money by not using it but dont want to risk mold or budrot.

Would you guys be worried with humidity in the high 60s when lights are off even with good air flow?
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u are pushing it good luck
 
pulpoinspace

pulpoinspace

Well-Known Member
hello

mold needs 3 things to grow. +60% RH, <70F, and poor air circulation

if you provide these three things, you will grow mold.

i have 65%-70% humidity sometimes during flower since i live in a humid place too. keep temperatures up and as much air circulation as possible. do not get buds wet when watering. do not mist plants or spray them with anything. turn up your exhaust. defoliate your plants so that fan leaves are not touching.

if you're worried about powdery mildew wash your harvest with hydrogen peroxide.

if you suspect botrytis throw that shit out and start over. might need dehumidifier.
 
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chronnie49

Well-Known Member
Everything looks fine so far. The buds are putting on weight and no signs of pm or mold with a few weeks to go until harvest.

Humidity is in the 40s for 12 hours per day so im not sure if that helps the situation. This is my first grow dealing with high humidity so Im not experienced when it comes to this situation but I would think i would see mold or pm by now if it was going to happen.
 
pulpoinspace

pulpoinspace

Well-Known Member
chronnie49 said:
Everything looks fine so far. The buds are putting on weight and no signs of pm or mold with a few weeks to go until harvest.

Humidity is in the 40s for 12 hours per day so im not sure if that helps the situation. This is my first grow dealing with high humidity so Im not experienced when it comes to this situation but I would think i would see mold or pm by now if it was going to happen.
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Mold can appear on the last day. Or can be inside the buds and not appear on the outside at all.

Not trying to scare you just be vigilant. Make sure those fans stay on.
 
B

Beachwalker

Well-Known Member
chronnie49 said:
I have 2 blue kush and 2 gorilla that are 6 weeks into flower and I'm wondering the higest humidity you have had during flower.

With lights on my humidity is mid to high 40s and 75 temp, lights off the humidity rises to high 60s and temps 64-68. I have an 8 inch exhaust fan, 12 inch oscillating fan blowing between the lights and canopy and a 9 inch fan on the floor blowing under the scrog net. I have a dehumidifier which lowers the lights off humidity to mid to high 50s but it uses 500 watts so trying to save a little money by not using it but dont want to risk mold or budrot.

Would you guys be worried with humidity in the high 60s when lights are off even with good air flow?
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Yes I've run into septoria almost every year with pretty much the same setup and conditions you've described, I'm between a saltwater marsh and the Atlantic Ocean so I often have high humidity

I use two 9 inch floor fans & I burn sulfur on a regular basis because I don't have the spare electricity to run a large dehumidifier in my grow room, but if you do I'd recommend you get that humidity in check, good luck!
 
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SPLFreak808

SPLFreak808

Well-Known Member
If i constantly go above 65% during lights out, i wouldn't be surprised if something starts to rot.

It's a/c + dehu for me, rare for the RH to dive below 70% in my city, stupid electric prices yet i suck it up because nothing is worse than a one man show loosing a third of his harvest.
 
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chronnie49

Well-Known Member
Thanks for the replies everybody.

The lowest i can get it is 58 percent running the dehumidifier but I'll stop being cheap and just run it for the next few weeks until harvest.
 
HitemwiththeHine

HitemwiththeHine

Well-Known Member
I would definitely run the dehumidifier at lights out, at the very least. I still have the giant dent in my ass from kicking myself after the first time I got mold. It's no fun, no sir.
 
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chronnie49

Well-Known Member
Yea ill run it during lights off. I dont think its necessary with lights on since humidity is in the 40s during that time. Not worth risking losing ounces for a little extra on the electricity bill
 
CoB_nUt

CoB_nUt

Well-Known Member
Air circulation is key and highly underestimated IMHO.Especially in humid environments.
If you look at certain vpd charts,(most aren't canna related) their golden ranges would seem conducive to mold for our beloved plant.
I've run 62-65% humidty accidentlly on purpose in late flower with no ill effects,mold or pm. Air circulation is key. If you don't have good airflow(above canopy,below canopy in between canopy) I wouldn't chance it and would find a way to get my humidty down around 50-55 in late flower if your environment isn't dialed in.
 
Renfro

Renfro

Well-Known Member
Some strains tolerate high humidity better than others. Here in Colorado I haven't had to lower humidity, actually the opposite I have to add it to achieve ideal growing conditions. So I can't say about the strains that I run now. When I was in Missouri we had high humidity issues. Some strains would get bud rott really easy while others would tolerate high humidity without any problems. I suggest researching the strains you run to see if they have any tolerance against mold and mildew.

A tip to help keep humidity lower when lights are off is to add heat. Warm air holds more water thus the air cooling off causes humidity to rise given a constant amount of water in the air.
 
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