High humidity in grow tent

Spragga

Member
I’m running a 4x4 grow tent with a 1200w viparspectra led light and a 4 inch carbon filter. I have three fans and two dehumidifiers in the grow tent but i can’t seem to get the humidity below 70% during flower. The humidity where I live is around 80%. Does anyone have any ideas how I can lower my humidity to suitable flowering conditions?
 

The303Yeti

Well-Known Member
I’m running a 4x4 grow tent with a 1200w viparspectra led light and a 4 inch carbon filter. I have three fans and two dehumidifiers in the grow tent but i can’t seem to get the humidity below 70% during flower. The humidity where I live is around 80%. Does anyone have any ideas how I can lower my humidity to suitable flowering conditions?
Make sure the carbon filer is allowing sufficient air through. Cheap, old/clogged, or too small inline fan will cause this.
 

ilovetoskiatalta

Well-Known Member
I’m running a 4x4 grow tent with a 1200w viparspectra led light and a 4 inch carbon filter. I have three fans and two dehumidifiers in the grow tent but i can’t seem to get the humidity below 70% during flower. The humidity where I live is around 80%. Does anyone have any ideas how I can lower my humidity to suitable flowering conditions?
How many plants ? What size pots? Passive intake or active? Any pics? Do you defoliate? Are you running Indicas or Sativas? What is your ambient temps in the room? What is your region so we know if it is fall or spring. This would be helpful.
 

JimmiP

Well-Known Member
In a 4x4, with two dehumidifiers? Are they running? I am not trying to cast aspersions upon what you are doing or your skills or knowledge in any way but that doesn't make any sense. Are you sure your hygrometer is functioning properly? And what do you have the dehumidifiers set too? BTW 70% is fine for the beginning of flowering.
Good luck friend!
 

JimmiP

Well-Known Member
Also are you running one dehumidifier in the tent and another in the space you are drawing air from? And where are you drawing air from?
 

ilovetoskiatalta

Well-Known Member
I’m running a 4x4 grow tent with a 1200w viparspectra led light and a 4 inch carbon filter. I have three fans and two dehumidifiers in the grow tent but i can’t seem to get the humidity below 70% during flower. The humidity where I live is around 80%. Does anyone have any ideas how I can lower my humidity to suitable flowering conditions?
How do you fit two 70 pint per day non commercial dehuyes in a 4x4? I am confused and I am not being confrontational. Just trying to help.
 

JimmiP

Well-Known Member
How do you fit two 70 pint per day non commercial dehuyes in a 4x4? I am confused and I am not being confrontational. Just trying to help.
Well, I didn't see where they quoted a size but I am wondering the same thing. I wouldn't have one in a 4x4. I use mine outside of the flowering room and it's currently a 4x8 (being expanded currently) And I only use one. And no problems unless the basement floods. When that happens it'll get a little above 70%. It's only for a day or two then. And if that happens I just move more air. I do have bigger fans though. Most of the time my humidity issues are from it being too low and I run a warm mist humidifier to deal with that.
I'm still wondering if the hygrometer is functioning properly.
 
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Spragga

Member
How many plants ? What size pots? Passive intake or active? Any pics? Do you defoliate? Are you running Indicas or Sativas? What is your ambient temps in the room? What is your region so we know if it is fall or spring. This would be helpful.
I have 6 plants in 3 gallon pots filler with coco. They are small autos, 4 indices and 2 sativas. The temps are about 25°c during the day and 18°c during the night. It’s currently fall and the relative humidity outside is about 80%. The intake is passive. Thanks for the help!
 

Spragga

Member
Also are you running one dehumidifier in the tent and another in the space you are drawing air from? And where are you drawing air from?
I am running two small dehumidifiers that pull about 500ml of water each per day inside the grow tent. I exhaust the air out a window and the intake is from a empty room.
 

The303Yeti

Well-Known Member
This is my set up I removed the two dehumidifiers which where hanging on the walls of the tent and placed them on the outside next to my intake
It get between 65 to 100% where I'm at. Get strains that are mold resistant. Mostly I just keep my grow very clean and wash my hands before I do any work.
 

osowhom

Well-Known Member
In a 4x4, with two dehumidifiers? Are they running? I am not trying to cast aspersions upon what you are doing or your skills or knowledge in any way but that doesn't make any sense. Are you sure your hygrometer is functioning properly? And what do you have the dehumidifiers set too? BTW 70% is fine for the beginning of flowering.
Good luck friend!
i am in week 3 my rh is around 45 or 50 lights on but at night it climbs to 75% as soon as lights come on i recirculate the air back down to 45 will this be a big problem? 3 plants organic soil not a tent but a big walk in closet
 

JimmiP

Well-Known Member
i am in week 3 my rh is around 45 or 50 lights on but at night it climbs to 75% as soon as lights come on i recirculate the air back down to 45 will this be a big problem? 3 plants organic soil not a tent but a big walk in closet
Are you saying your fans and dehumidifiers shut down with your lights?
Anyway there's always a rise in humidity after lights out. I would try to make sure the air I was drawing into the grow was as dry as it needed to be before it entered. If you are moving enough air in the space the plant is in, then its not in there very long and should be dealt with before hand.
Problems can (but don't always) arise from the humidity being too high, especially after lights out. Keep the rh in your house lower if you can.
 

JimmiP

Well-Known Member
I am running two small dehumidifiers that pull about 500ml of water each per day inside the grow tent. I exhaust the air out a window and the intake is from a empty room.
Thats obviously not enough. Are you running a whole house humidifier?
Get a bigger dehumidifier (if you can) and dry the air that is entering tent before it goes in. Then maybe the two small ones inside the tent, can do a better job with the humidity spike at lights out.
 
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hotrodharley

Well-Known Member
This situation comes up regularly. You are not going to control humidity in a tent sitting in a room with high humidity. Basically you need to dehumidify the entire house.
 

madvillian420

Well-Known Member
i am in week 3 my rh is around 45 or 50 lights on but at night it climbs to 75% as soon as lights come on i recirculate the air back down to 45 will this be a big problem? 3 plants organic soil not a tent but a big walk in closet
Sounds similar to my setup, it can be problematic. I had about 15 shirts still hanging in the corner of my closet and they all got moldy and were absorbing the moisture when it was lights off with high humidity. I got sick of the humidity spikes and cut a hole and installed a bathroom type fan in the ceiling leading to my attic that now runs 24/7
 

myke

Well-Known Member
I have a 45 pint in a 5x5 recessed into the wall.Have it on constant and a timer 15 on 15 off at night.works well.Humidity in my house sits at 40-50.Lights on its 15 on 45 off.Makes a lot of heat i pipe it down to the floor.
 
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