Did my humidity increase because the plant grew ?

bk78

Well-Known Member
Sorry if I wasn’t clear.
I have two 4inch inline fans and one Booster fan. With two regular fans circulating air inside tent.
1 inline fan is blowing air into the tent, at bottom.
1 inline fan at top extracting air.
1 inline booster fan at top also extracting air.
(When I starter having humidity issues I added the booster fan as a second extraction fan.)
Both extraction fans are connected to carbon filters.
Where are you venting the air from the tent to?
 

Star Dog

Well-Known Member
Sorry if I wasn’t clear.
I have two 4inch inline fans and one Booster fan. With two regular fans circulating air inside tent.
1 inline fan is blowing air into the tent, at bottom.
1 inline fan at top extracting air.
1 inline booster fan at top also extracting air.
(When I starter having humidity issues I added the booster fan as a second extraction fan.)
Both extraction fans are connected to carbon filters.
Right OK I'm with you, what your experiencing is normal, to lower the rh you need a dehum or a higher temperature, your never going to get below the intake rh%.

That isn't as bad as it might sound rh% can be difficult to understand, although your rh% is reading higher doesn't necessarily mean that there is more moisture in the air it's only the temperature dropping reflecting the air saturation for that temperature, so in essence it's the same amount of moisture passing through the tent as when the light is on.
Can that amount of rh cause bud rot? It hasn't in the past but I'd rather not risk it now.
 

Dontjudgeme

Well-Known Member
Ok.. so, Run the huey with the exhaust off.
Do I kept the intake fan running?
Also, there’s two 6” fans inside the tent pointed upwards blowing the heat away from plant, keep these running too ?
Oscillating fans do a really good job of controlling a mold outbreak, but won’t have much affect on the humidity itself. If your dehuey is connected to a humidity controller, it will only kick in when then the humidity rises above what you set. If your exhaust is on with the lights, and it should be, humidity shouldn’t be much of a problem. It’s the night time spikes that need controlling. Shouldn’t be much heat in the tent at lights out anyway. Some people run their exhaust 24/7, this should completely eliminate high humidity levels altogether, even with the lights off. But running the exhaust with a dehuey at the same time is kind of counter productive. My exhaust only kicks in when the temp rises above what I set, when the exhaust turns off, humidity rises, then my humidity controller kicks in the dehuey. They both do a back and forth all day. Once lights are off, the exhaust doesn’t run as much, this is when the dehuey does most of its work. I’m in a 3x3 so I have more plants to control, so a 2.5x2.5 should be a lot easier to maintain. Without a temp and humidity controller, you will find it very challenging to control your environment.
 

Jettman1

Active Member
Oscillating fans do a really good job of controlling a mold outbreak, but won’t have much affect on the humidity itself. If your dehuey is connected to a humidity controller, it will only kick in when then the humidity rises above what you set. If your exhaust is on with the lights, and it should be, humidity shouldn’t be much of a problem. It’s the night time spikes that need controlling. Shouldn’t be much heat in the tent at lights out anyway. Some people run their exhaust 24/7, this should completely eliminate high humidity levels altogether, even with the lights off. But running the exhaust with a dehuey at the same time is kind of counter productive. My exhaust only kicks in when the temp rises above what I set, when the exhaust turns off, humidity rises, then my humidity controller kicks in the dehuey. They both do a back and forth all day. Once lights are off, the exhaust doesn’t run as much, this is when the dehuey does most of its work. I’m in a 3x3 so I have more plants to control, so a 2.5x2.5 should be a lot easier to maintain. Without a temp and humidity controller, you will find it very challenging to control your environment.
I have a temp a humidity controller connected to my exhaust fan. It has to always be on With the light or the heat goes up to 89 degrees, it’s back and forth
 

Jettman1

Active Member
Right OK I'm with you, what your experiencing is normal, to lower the rh you need a dehum or a higher temperature, your never going to get below the intake rh%.

That isn't as bad as it might sound rh% can be difficult to understand, although your rh% is reading higher doesn't necessarily mean that there is more moisture in the air it's only the temperature dropping reflecting the air saturation for that temperature, so in essence it's the same amount of moisture passing through the tent as when the light is on.
Can that amount of rh cause bud rot? It hasn't in the past but I'd rather not risk it now.
... I blacked out all light into the room, so now I can leave the tent open with the plant in the dark, to counter act the humidity in the tent.
 

Trickyticky

Well-Known Member
I've found constant extraction to be the best all round solution to heat and humidity, the UK rh% is usually between 70/85% so trying to get below that at light out without heating and something removing moisture is near impossible.
I think a dehum is a must have for any UK grower due to our ave rh%, but it also adds heat to the tent my 5x5 at light out is 52/56% 19/21c using a 160w dehum with the extraction fan idling at around 10/12%
I use oil rad for lights out so have extraction and intake on at all times
 

Dontjudgeme

Well-Known Member
I have a temp a humidity controller connected to my exhaust fan. It has to always be on With the light or the heat goes up to 89 degrees, it’s back and forth
Where you have your probe plays a role as well. That small of a tent tends to heat up rather quickly if you have too strong of a light. If it’s hot in the room the tent is in, the inside of the tent will be also, no matter how long or hard you run the exhaust, because all you’re doing is bringing that outside heat inside. This is why a lot of people grow outside during the summer because the electric bill can get pretty pricey trying to keep that room cool. Can’t beat the suns free energy, although I do understand that everyone doesn’t have the luxury of growing outdoors. I don’t have that luxury either, so a pricey electric bill it is.
 

Rurumo

Well-Known Member
You're probably going to have to get a dehumidifier for the entire room, not a little one for the box. Those small dehumidifiers do fine in small spaces, but they are pointless if you're venting from and to the same room because the air in the box is constantly being exchanged. Also, those small dehumidifiers use very little power because they don't use compressors, but they also remove a very feeble amount of water. You should look at the 30 pint dehumidifiers on Amazon that are for 1,000-1,500 sq feet-those claims are pretty much BS, ignore them. Be sure to get one that is UL or ETL listed and check the comments/questions for the amps/watts they use. I use a Homelabs unit "rated" for 1,500 sq feet and it uses about 250 watts of power. It's enough to keep the humidity down in my room, and thus also my tent, with good air exchange. They do use a fair bit of power so make sure you plug it into a circuit that has enough amps to safely run it-I only say this because a lot of people plug everything into a single power bar on a single 15 amp circuit (which you should only be running 1,200 watts or less on) and another high powered device might push them over their limit.
 

Jettman1

Active Member
Where you have your probe plays a role as well. That small of a tent tends to heat up rather quickly if you have too strong of a light. If it’s hot in the room the tent is in, the inside of the tent will be also, no matter how long or hard you run the exhaust, because all you’re doing is bringing that outside heat inside. This is why a lot of people grow outside during the summer because the electric bill can get pretty pricey trying to keep that room cool. Can’t beat the suns free energy, although I do understand that everyone doesn’t have the luxury of growing outdoors. I don’t have that luxury either, so a pricey electric bill it is.
Are you pulling fresh air in from outside
No.. but since my last post I removed the second extraction fan and Repositioned it as an intake fan and the temp and humidity are much better.
I have another question:
it’s exactly two weeks into bloom, so as I’ve read, I removed the four lowest shoots Carefully with a razor. (All but one shoot is level with canopy, but it’s close).
I also gave it bloom nutrients for the first time.
there's like 18 little bud sites along the top of the two main branches (it was topped), extending out to the main flowers.

So, my question is:
At what point do I start removing Fan leaves ?
For max yield do I keep all the little bud sites that are canopy level or remove some to focus energy to other sites?
I really appreciate your help, I’m excited. First time, almost there.
 

Dontjudgeme

Well-Known Member
No.. but since my last post I removed the second extraction fan and Repositioned it as an intake fan and the temp and humidity are much better.
I have another question:
it’s exactly two weeks into bloom, so as I’ve read, I removed the four lowest shoots Carefully with a razor. (All but one shoot is level with canopy, but it’s close).
I also gave it bloom nutrients for the first time.
there's like 18 little bud sites along the top of the two main branches (it was topped), extending out to the main flowers.

So, my question is:
At what point do I start removing Fan leaves ?
For max yield do I keep all the little bud sites that are canopy level or remove some to focus energy to other sites?
I really appreciate your help, I’m excited. First time, almost there.

I try not to remove any fans if I can help it. If I do it’s more for light penetration to the lower sites. Other than that I don’t touch my fans, they are the solar panels to your plants growth. Wanna see a plant grow at a snails pace, remove the fans leaves.
 

Boatguy

Well-Known Member
I dont think the humidity levels the op is worried about are a problem. I get humidity spikes at lights out as high as 80 but have good circulation. Same size tent by the way.
 

Dontjudgeme

Well-Known Member
I dont think the humidity levels the op is worried about are a problem. I get humidity spikes at lights out as high as 80 but have good circulation. Same size tent by the way.
I don’t either, but I like to walk on the side of caution. I have the same size tent for my veg and I purposely let me RH get into the mid 70’s, of course with good air circulation. But I’m not sure I would follow that same process in flower. 60 is about as high as I’m willing to push it. But that’s me
 

Boatguy

Well-Known Member
I don’t either, but I like to walk on the side of caution. I have the same size tent for my veg and I purposely let me RH get into the mid 70’s, of course with good air circulation. But I’m not sure I would follow that same process in flower. 60 is about as high as I’m willing to push it. But that’s me
I have a lack of control in the lil tent. I do have a tiny dehuey, but not convinced it does much.
The air circ i give most of the credit too
 

Star Dog

Well-Known Member
I've got my humidity to around 55% with the light on and I've started tonight running a dehumidifier to take down rh a bit but more importantly to raise the temperature, yesterday morning the canopy was 23.7c and below 19.2c the dehum raises the temperature to 26c above and 22/23c below.
Constant ventilation below the canopy drives down the temps if I switch it to Thermostat the rh can get up to 58/60% between cycles?

What do you think, constant with the dehum, Thermostat control with no dehum but slight raise in rh or low temps with the acceptable rh%?
Just curious what others would do, I could happily live without the additional cost of the dehum?
 

Star Dog

Well-Known Member
No.. but since my last post I removed the second extraction fan and Repositioned it as an intake fan and the temp and humidity are much better.
I have another question:
it’s exactly two weeks into bloom, so as I’ve read, I removed the four lowest shoots Carefully with a razor. (All but one shoot is level with canopy, but it’s close).
I also gave it bloom nutrients for the first time.
there's like 18 little bud sites along the top of the two main branches (it was topped), extending out to the main flowers.

So, my question is:
At what point do I start removing Fan leaves ?
For max yield do I keep all the little bud sites that are canopy level or remove some to focus energy to other sites?
I really appreciate your help, I’m excited. First time, almost there.
I'm with @Dontjudgeme I wouldn't touch any food storing, active cooling solar panels.
 
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