humidity at night

oill

Well-Known Member
Hi all

I am getting good humidity of about 45 with a temp of about 28c when lights are on, but when they are off it shoots up to about 70 percent and temp of about 20c. Temps are ok for me but humidity is too high... All fans stay on all the time...

Fans... mm duct fan extracts over a 100 mm cool tube with my 400 w . A 100 mm inlet fan and a 5 inch fan tp move air around inside. Tent is 80 by 80cm.

Question is... How do I reduce humidity? I have a heater.... Should I use that?
 

eboo

Active Member
I wouldn't add heat, that just promotes mold especially with high humidity. Add more airflow, try to cycle more fresh air in and out. If you are just swirling the same air around nothing will change. Also make sure you don't have excess water just hanging around, water early in the day to prevent water sitting at night.
 

SnapsProvolone

Well-Known Member
Add heat.

As air temps drop, RH% rises, given a fixed amount of moisture.

Also, dehumidifiers work less efficiently in cooler temperatures.

Double whammy of suckiness. :/
 

oill

Well-Known Member
Whammy!!!!!

There is plenty of air movement, and there is no water lying about. I put the heater on... Will see what that does.

Would this humidity result in longer ripening times?
 

Spirallight

Active Member
Whammy!!!!!

There is plenty of air movement, and there is no water lying about. I put the heater on... Will see what that does.

Would this humidity result in longer ripening times?
Likely result in boytris. Some people call it bud mold. Deal with the humidity. Run a dehumidifier.
 

Helmut79

Well-Known Member
The question is, what is RH % outside of the grow room? When you're taking in air of 70% RH, you won't benefit from ventilating faster, in my opinion.

I had the same problem and I went crazy by ventilating up to 2 times per minute, only to see that nothing changed in terms of RH.

Heater or dehumidifier would be the solution I guess.

I would keep ventilation at 0.25 x per minute (once every 4 minutes).
 

oill

Well-Known Member
Add heat.

As air temps drop, RH% rises, given a fixed amount of moisture.

Also, dehumidifiers work less efficiently in cooler temperatures.

Double whammy of suckiness. :/
Would the high humidity effect ripening time?
Likely result in boytris. Some people call it bud mold. Deal with the humidity. Run a dehumidifier.
Yep... Added a heater and dehumidifier... Now running at...

Night 23c 50% RH
Day 27-28c 40% RH

Will this speed up finishing though?
 

Spirallight

Active Member
Would the high humidity effect ripening time?


Yep... Added a heater and dehumidifier... Now running at...

Night 23c 50% RH
Day 27-28c 40% RH

Will this speed up finishing though?
No. The only thing that speeds up finishing is very high levels of light and co2 combined. If your flowering times are too long, look into strains that finish faster.
 
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