Excessive uncontrollable humidity at night

[Keithandthegreen]

Hello I am having a difficult time. This is not my first grow & I've never had this issue before.

I have a 4x4 in a lung room with a window ac & 2 dehumidifiers & a reptile humidifier feeding inside the tent. as well as a wifi controller connecting the humidifier & dehumidifier. I have a 6"inline fan that exhausts constantly I usually keep it at a 4 until late flower.

Overnight lately my humidity is shooting from low 60s to 80s. I get both dehumidifiers running & turn up my exhaust on the tent but it is making almost no difference. I have defoliated my tent pretty thoroughly & idk what to do from here. 0 standing water in the tent I have a table with a condensate pump under it pumping to a drain tub. I've never had this issue & I just started flower I'm worried if I don't get this fixed soon it will effect my buds when they start forming.

Daytime temps are 78 & 62 rh average.

 

[Shaded_One]

"I have a 4x4 in a lung room with a window ac & 2 dehumidifiers & a reptile humidifier feeding inside the tent" this sounds a little counterproductive? Why are you running a de-humidifier and a humidifier in the same small tent? Easy things to do are vent your exhaust out a window instead of back into the room. Have the A/C & de-humidifier sucking moisture out of the room that you intake from.

 

[Madmax]

I added heat to mine.550w .extraction fan plugged into inkbird set temp to 22.9 nd now my rh is in the 40s overnight..i also use heat lights on to get the room reaching temp then extraction fan comes on before humidity rises and keeps it in check

 

[Keithandthegreen]

"I have a 4x4 in a lung room with a window ac & 2 dehumidifiers & a reptile humidifier feeding inside the tent" this sounds a little counterproductive? Why are you running a de-humidifier and a humidifier in the same small tent? Easy things to do are vent your exhaust out a window instead of back into the room. Have the A/C & de-humidifier sucking moisture out of the room that you intake from.

The dehumidifier is outside of the tent dehumidifying the lung room. & the humidifier only kicks on when rh drops below the set point. This has let me control the temp & humidity to great effect in the past.

 

[Shaded_One]

The dehumidifier is outside of the tent dehumidifying the lung room. & the humidifier only kicks on when rh drops below the set point. This has let me control the temp & humidity to great effect in the past.

I wouldn't even bother with the humidifier if you are battling humidity issues. To give you some context - I am in Canada where it is EXTREMELY dry here. Like when I start my grows my RH is <30%. As the plants grow larger and transpire more my RH balances out to around ~50%. My point is if you are in an area where the humidity is naturally high you shouldn't have to do much if anything at all to maintain a decent RH. Maybe look into getting a controller for the exhaust fan and just have that kick in when RH gets too high vs using all these appliances to try to control it.

EDIT: 4x4 with 600w of LED, temp is around 30c, RH around 50 - exhausting into the room I am intaking from and my windows are open 24/7.

 

[Keithandthegreen]

I added heat to mine.550w .extraction fan plugged into inkbird set temp to 22.9 nd now my rh is in the 40s overnight..

Not a bad idea I might try that. The idea is by adding heat I am lowering the rh & then controlling temp with the fan?

 

[Keithandthegreen]

I wouldn't even bother with the humidifier if you are battling humidity issues. To give you some context - I am in Canada where it is EXTREMELY dry here. Like when I start my grows my RH is <30%. As the plants grow larger and transpire more my RH balances out to around ~50%. My point is if you are in an area where the humidity is naturally high you shouldn't have to do much if anything at all to maintain a decent RH. Maybe look into getting a controller for the exhaust fan and just have that kick in when RH gets too high vs using all these appliances to try to control it.

I have a controller for the fan. My issue is that no matter how high I turn the fan on it is not extracting humidity. The humidifer is also connected to a controller so it is not always on. It is probably on less than an hour a day.

 

[Shaded_One]

I have a controller for the fan. My issue is that no matter how high I turn the fan on it is not extracting humidity. The humidifer is also connected to a controller so it is not always on. It is probably on less than an hour a day.

What size is your extraction fan? And are you exhausting directly outside?

 

[Keithandthegreen]

What size is your extraction fan? And are you exhausting directly outside?

6" inline fan with a carbon filter. Exhausting outside is a big no where I'm at. Exhaust straight into lung room with dehumifier & window ac.

 

[Madmax]

Not a bad idea I might try that. The idea is by adding heat I am lowering the rh & then controlling temp with the fan?

That too and reaching my set point quicker so exhaust is cutting on more often..it solved my rh problems big time as i was getting mold...humidity spikes..

 

[Shaded_One]

6" inline fan with a carbon filter. Exhausting outside is a big no where I'm at. Exhaust straight into lung room with dehumifier & window ac.

I have a 6" that runs 24x7 at about 20% speed to maintain 50% with no A/C or dehumidy and fresh outside air coming in via windows. I would be curious to see what your RH is like in the tent with the exhaust at 50% with no controller kicking it on and off.

 

[Keithandthegreen]

I have a 6" that runs 24x7 at about 20% speed to maintain 50% with no A/C or dehumidy and fresh outside air coming in via windows. I would be curious to see what your RH is like in the tent with the exhaust at 50% with no controller kicking it on and off.

lights on it would get down to 40% i know because ive forgot to fill the humidifier once or twice. & i don't really want to maintain 50% rh.

I'm chasing vpd, & I'm cropsteering so at different points in the flowering stage I'm looking for different temps & rh to manipulate the rhizospheres uptake to control drybacks & soil ec. It's important to me to control temps & rh within 5 degrees. During the daytime my tent conditions are perfect. & I'm usually not too concerned at night as long as it doesn't get too hot or cold at night. But this is new.

 

[Shaded_One]

lights on it would get down to 40% i know because ive forgot to fill the humidifier once or twice. & i don't really want to maintain 50% rh.

I'm chasing vpd, & I'm cropsteering so at different points in the flowering stage I'm looking for different temps & rh to manipulate the rhizospheres uptake to control drybacks & soil ec. It's important to me to control temps & rh within 5 degrees. During the daytime my tent conditions are perfect. & I'm usually not too concerned at night as long as it doesn't get too hot or cold at night. But this is new.

I would rather have 40% vs 80% and risk mold but that's just me sounds like you just gotta play with your controller or get a controller and play around with some things to adjust for the night time swing