Hey guys, I'm having what I think are some serious humidity problems. I have a rubbermaid grow box (2 31 gal containers). They are inside my closet. Inside are 2 plants in soil. For light I'm using a 150W HPS. I have 2 passive intakes and one 33cfm intake fan. I also have a 33cfm exhaust fan hooked up through dryer vent tubing to a homemade carbon filter. I just switched to 12/12 on May 17.

I am having problems with my humidity getting high at night when the lights are off. During the day, if i can keep the closet door open, humidity stays around 35-45%. However, at night with the closet door closed and sealed so no light comes through, I have humidity get up to 80 or even 90%. My plants haven't started to flower yet though I see signs of preflowers.

Last night I put a bowl of rice in there to use as a dessicant but it didn't seem to work at all. What can I do to get the humidity down to where it needs to be? Oh yeah, temps during the day range from 77-80 deg Farenheit and at night hover around 68 deg Farenheit.

Any help is very much appreciated. Thanks!

Run your fans 24 hours a day

Also, 33 cfm is really really REALLY as small amount. Air flow is key.

Ok, thanks for the advice...fans are running 24 hrs a day, but i guess they are too small. gonna have to get some bigger ones i guess. thanks!

OR/and your could get a small dehumidifier.

So with our your lights on and your fans running your plants give off more moisture? How warm is your closet during the day.. Your plants should breath more during the light I would think. hmmm...

When you run a fan thru tubing and a filter it gets much less flow. So figure that one 33 cfm fan to be closer to 15 then 30. Air flow can be tricky.