Humidity issues, lost on what to do

Having humidity issues in my grow tent I have a 3x3 tent with a 4 inch extractor fan with carbon filter. I have 1 clip on 12 inch oscillating fan and a tower fan on oscillating aswell. Lights are off between 6am and 6pm and I’m getting high humidity during this time. Nothing seems to be working to reduce the humidity. Does anyone have ideas to resolve this issue I’m lost on what to do


Try sticking a dehumidifier into the same room your tent is in. All your fans are doing is moving the same moist air around. Your extractor fan will suck moist air out but if the air going in is moist as well then nothing will change. What is your humidity sitting at just now

65 RH with lights off

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I moved the dehumidifier from in the tent to outside the tent in the room to see if that will help


What stage are you at just now

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Day 5 flower

Are you leaving lots of standing water in pot trays?

What are your temperatures lights on and off?when lights go off and the temperature drops the rhythm will go up. Maybe a small heater to keep the temp more stable if it’s dropping after lights off will keep the rh from rising.

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No water being left in pot trays

Lights on its around 28-29 with humidity of 50

Try a small heater to keep temps stable and see if the humidity also stabilizes I believe it will. Or dehumidifier

Theres a few things u can do .1,is to get a bigger exshust system go to a 6inch 2, get a dehumidifier 3, by some bicarbonate soda and put it in a bowl and place that bowl in ur tent the bicarbonate soda should draw out the extra moisture in ur tent 4,get two more clip on fans add more air flow in ur tent and open ur vents in ur tent


Here in the nigh plains desert I would love that humidity! 25% ambient. I added three home humidifiers using a gallon each a day and I hit ~ 30ish. Add two wet towels in the tent and maybe 45!

Another tip for pulling humidity down is bowls of salt in your tent. Cheaper than a dehumidifier as well

If u have a dehumidifier put that in the room next to the tent where the intake is for the tent. Put a tube going from where the intake is to where the dehumidifier blows the air out. It will be warmer dry air being blown into the tent to keep it a bit warmer and less rh. Hope u get what I mean.


What is the humidity in the room the tent is in?

I use my room as a lung for the tent… A large 70 pint dehumidifier with a drain hose in the room.

The tent may need more air flow through the tent. Set the room dehumidifier to the desired RH, turn up your tents exhaust fan… Maybe add an inline fan forcing air into your input air port.

Have a cool mist humidifier, inside the tent, connected to an inkbird humidity controller humidifier socket and on its dehumidifier side socket plug in the input air port inline fan. Set the inkbird to desired humidity… You can adjust the +/- of rh on both humidifier and dehumidifier to stabilize the rh.

With this setup I can completely control my humidity. Similar for temps.

If your exhaust and intake ports are too small go bigger if possible… 6". AC infinity… Great stuff.

Im thinking of ordering a 6 inch exhaust fan that has the auto mode where it can turn itself off or on based on the humidity and temp and then using my 4 inch I have now as a intake. Where im from its summer and the days are getting to 98.6 F which is causing my tent to hit temps of 91 F

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More air flow will definitely help… I have AC Infinity 6" on both my 4x4s… I usually set it at 3 all the time to let the plants breathe fresh air at all times… But it’s now Winter here and with temps dropping into the 10F-20F area… I have left it set at 1 to let less colder air in. I have an electric oil filled radiator in them with inkbird temp controller controlling temps.

Good luck!

Alot of portable AC units have a dehumidifier built in. This would be perfect if you got higher temperatures as well.
I control 3 tents in same room by focusing on keeping the room at or just below what I want the tents to be. Once the room is in range the tents fall right in place.
Like others have said, air flow makes little to no difference if the air coming and going is the same RH. The only way to drop it is to remove moisture from the air some how weather it be inside tent or outside tent in the room “aka” the lung…

I can manage to raise RH quite a bit in my germination tent by lowering the airflow and running a small humidifier inside the tent. While keeping my lung some 20% lower RH at times.

But it’s not so easy going the other direction :confused:.
GL though, you have option to choose from that will all work.

So you think getting a bigger exhaust won’t help the situation I need an ac unit instead?

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