To much humidity

i have been flowering some ladies unde a 400w hps and have a humidity problem during lights off it goes around 75 percent. i will be buying a dehumidifier but not now, i have been flowering for 1 week so i must hurry i know. any help on how to bting it down cheap?

Tribalbandit said:

i have been flowering some ladies unde a 400w hps and have a humidity problem during lights off it goes around 75 percent. i will be buying a dehumidifier but not now, i have been flowering for 1 week so i must hurry i know. any help on how to bting it down cheap?

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FANS. Air circulation.

atidd11 said:

FANS. Air circulation.

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+1,000,000
use a good exhaust system even during lights out. I mean your ambient humidity will always play a huge role, but if you wanna lower your humidity by 25-30% in a pinch just move more air. More air is seldom a bad thing anyway.

ok thanks ill put one more fan in my flowering room for now, a friend of mine told me to put a bucket of ciment that it would collect all the humidity is it possible?

im in the same boat. in a 3x3x6 grow tent. have a coolable hood that pulls air straight through vents via basic duct fan. when i zip up the tent, the oscillating fan is still running in there and the top vent is open but humidity is still around 70% at night.

what im going to do is
1) buy an intake fan for the bottom vent.
2)get a peice of plywood for support and cut out a circle to place another duct fan to pull air up through the top vent.
3)pray its not too noisy at night, since my neighborhood is very compact

just have to wait for next check. ill let you know how its going.
it feels ok to know people are in my boat right now.

DankShasta said:

+1,000,000
use a good exhaust system even during lights out. I mean your ambient humidity will always play a huge role, but if you wanna lower your humidity by 25-30% in a pinch just move more air. More air is seldom a bad thing anyway.

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i put in a smaller exhaust system that as very cheap and silent, i do have a little kitchen exhaust that i bought for when the smell would be more intense. looks like i will be putting it up when my lights go on, thanks

Tribalbandit said:

i put in a smaller exhaust system that as very cheap and silent, i do have a little kitchen exhaust that i bought for when the smell would be more intense. looks like i will be putting it up when my lights go on, thanks

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the only prblem is that its noisy and i live in a apartment.

decrease temp gradient and you won't have those RH swings. a heating pad, or seedling mat. as air cools at night, it becomes relatively wetter. lose the temp swings and the RH will stabilize.
imo

scroglodyte said:

decrease temp gradient and you won't have those RH swings. a heating pad, or seedling mat. as air cools at night, it becomes relatively wetter. lose the temp swings and the RH will stabilize.
imo

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Thats a good point. 55% humidity at 78 degrees, is 95% humidity at 55 degrees. 75 lights on, 65 lights off, and exhaust.

A dehumidifier will only lower it about 10%.

I'm not sure why it's such a concern. I'll bet raising that 55 dark temp to 70 with a small heater will lower it 10% too.

thanks for all the great info will be working on this problem right when my light turn on.

well got to problem solving and traded my exhaust system, out with the old cheap silent one and in with a new very noisy one. Put in radiotor to help with the temps when lights are off. The early spring days have been very rainy and cold so iI am sure its fucking up with my enviroment. It should be getting hot any time soon so lets see what will happen, I am not using the radiator yet because i wanted to see how the exaust will do if workin 15 min on and 15 of and the fan is also at the same time cycle, during the exausts pause. I took a peak in and go my thermometer out and the reading is at 75 % humidity still damn it. will have to get the radidor working.

For venting: You want more air being sucked out than blown in. This will reduce the humidity decrease chances of mold and pests. You want one Fan blowing air into the environment, one Fan sucking air out of the environment and one fan blowing air around in the environment. If you have these three things and your night humidity is still messed up, or if your cold air in fan is too cold at night, they make photosensitive fan speed controllers that you can preset at times and temperatures you ideally want for your day/night cycle.

Illegal Smile said:

A dehumidifier will only lower it about 10%.

I'm not sure why it's such a concern. I'll bet raising that 55 dark temp to 70 with a small heater will lower it 10% too.

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I had some powdery mildew when my room was running at 50-70% RH last cycle.
I thought it was under control, but the powder came back right before harvest. I threw 20 full grown ladies into the trash,,,
Here is the new grow 28 days in flower. Made some changes including a dual zone mini split ac that sucks about 6-7 gallons of water out of the room every day. Humidity here has been a constant 65% for 2 months now. I'm trying to maintain 40-45%. PM sucks