Reduce Temp drop and high humidity

Djdanko23 · Mar 21, 2020

Going to flip to flower on about April 1st. I am beginning to become concerned with the high humidity due to the temperature drop when the lights go off.
Temps go from Mid 70's to 60 after the lights have been off for an hour or so. The humidity spikes to nearly 80%. I have messed with the setting on my exhaust fan allowing it to kick on sooner to try to suck the humidity out, but it's not helping too much. Today I opened the bottom vents on my tent to see if that will help, but that is not an option during flower. Do I run a dehumidifier outside the tent? Any suggestions?

Running a CMH 630 at half power in a 4x4 tent.

MIGrampaUSA · Mar 21, 2020

Djdanko23 said:
Going to flip to flower on about April 1st. I am beginning to become concern with the high humidity due to the temperature drop when the lights go off.
Temps go from Mid 70's to 60 after the lights have been off for an hour or so. The humidity spikes to nearly 80%. I have messed with the setting on my exhaust fan allowing it to kick on sooner to try to suck the humidity out, but it's not helping too much. Today I opened the bottom vents on my tent to see if that will help, but that is not an option during flower. Do I run a dehumidifier outside the tent? Any suggestions?

Running a CMH 630 at half power in a 4x4 tent.

5 x 5 tent, a temp controller, an intake fan, and exhaust fan, and a circulating fan. - This is what I use to keep humidity down right now.

I hung a 1" x 10 x 5' board in my tent to make a shelf. The bottom of the shelf is at light level and can be adjusted to match light heights. My intake and circulation fans are always on. When my temp controller hits 78 it exhausts my tent. I have 11 plants at the start of 12 x 12 light cycle and my humidity does not go over 60%.

I have a dehumidifier that I can put on that shelf too. I haven't used it yet but when humidity builds even more as the tent fills, I can use that to keep it where I want it to be. If you decide to put any electronics inside the tent, cover any LCD or light that it emits with black electrical or duct tape. (make sure no cords are on the ground. plug into gfi receptacle for extra precautions)

Beachwalker · Mar 21, 2020

Djdanko23 said:
Going to flip to flower on about April 1st. I am beginning to become concerned with the high humidity due to the temperature drop when the lights go off.
Temps go from Mid 70's to 60 after the lights have been off for an hour or so. The humidity spikes to nearly 80%. I have messed with the setting on my exhaust fan allowing it to kick on sooner to try to suck the humidity out, but it's not helping too much. Today I opened the bottom vents on my tent to see if that will help, but that is not an option during flower. Do I run a dehumidifier outside the tent? Any suggestions?

Running a CMH 630 at half power in a 4x4 tent.

Put some silver ducting in the bottom Inlet and curve it around an outside corner so it will block the light and leave it always open, and leave the extraction fan on all the time; also add some floor fans if you can't get a humidifier

BurnzYzBudZz · Mar 21, 2020

MIGrampaUSA said:
5 x 5 tent, a temp controller, an intake fan, and exhaust fan, and a circulating fan. - This is what I use to keep humidity down right now.

I hung a 1" x 10 x 5' board in my tent to make a shelf. The bottom of the shelf is at light level and can be adjusted to match light heights. My intake and circulation fans are always on. When my temp controller hits 78 it exhausts my tent. I have 11 plants at the start of 12 x 12 light cycle and my humidity does not go over 60%.

I have a dehumidifier that I can put on that shelf too. I haven't used it yet but when humidity builds even more as the tent fills, I can use that to keep it where I want it to be. If you decide to put any electronics inside the tent, cover any LCD or light that it emits with black electrical or duct tape. (make sure no cords are on the ground. plug into gfi receptacle for extra precautions)

Can you Elaborate more on the “if you have any electronics inside the tent” part. I don’t quite understand this. Aren’t fans and dehumidifier electronic? What exactly do we cover with electrical tape?

MIGrampaUSA · Mar 21, 2020

BurnzYzBudZz said:
Can you Elaborate more on the “if you have any electronics inside the tent” part. I don’t quite understand this. Aren’t fans and dehumidifier electronic? What exactly do we cover with electrical tape?

You cover anything that emits light with tape. If it's on emitting light during the dark cycle, it could be enough light to stress the plants.

My fans don't have anything that emits light, but my heater and my dehumidifier do. The LCD is covered with black tape on my heater.

BurnzYzBudZz · Mar 21, 2020

MIGrampaUSA said:
You cover anything that emits light with tape. If it's on emitting light during the dark cycle, it could be enough light to stress the plants.

My fans don't have anything that emits light, but my heater and my dehumidifier do. The LCD covered with black tape on my heater.

Got it. You’re talking about flowering. I understand now. Thank you for the clarification. Definitely need it pitch dark. Have a good one.
Burnz

Dirtbag · Mar 21, 2020

Yeah, dehu outside the tent.

MIGrampaUSA · Mar 21, 2020

BurnzYzBudZz said:
Got it. You’re talking about flowering. I understand now. Thank you for the clarification. Definitely need it pitch dark. Have a good one.
Burnz

Temperature difference between high temp and low temp also influences humidity. I have my low temp set so my heater comes on at 69 degrees. As the temperature falls in the tent, more humidity builds and you may even see condensation on your plants at lights on. Raising night time temps helps control this as does the air flow.

Djdanko23 · Mar 21, 2020

Beachwalker said:
Put some silver ducting in the bottom Inlet and curve it around an outside corner so it will block the light and leave it always open, and leave the extraction fan on all the time; also add some floor fans if you can't get a humidifier

I already the duct on one side on one. I have 4 fans. top 2 above canopy and 2 below. Bottom are always on and top come on with lights.

Exhaust fan is set to kick off at high temp of 78 and high humidity of 70%

MIGrampaUSA · Mar 21, 2020

Djdanko23 said:
I already the duct on one side on one. I have 4 fans. top 2 above canopy and 2 below. Bottom are always on and top come on with lights.

Exhaust fan is set to kick off at high temp of 78 and high humidity of 70%

How well can you control your "night time" temperatures? If you keep your low temps to 68-70 degrees, you will have better humidity control.

Beachwalker · Mar 21, 2020

Djdanko23 said:
I already the duct on one side on one. I have 4 fans. top 2 above canopy and 2 below. Bottom are always on and top come on with lights.

Exhaust fan is set to kick off at high temp of 78 and high humidity of 70%

What do you mean kick off? you never want your humidity to hit 70%, 60 Max in veg and you're going to want to keep it between 40 and 50% in bloom so again, keep it on all the time, or set it to come on when it hits 60% at the very least

Edit: also 60° is too low for the dark period. Keep it above 65, ideally 68 to 72 is what I work with in the winter

MIGrampaUSA · Mar 21, 2020

Beachwalker said:
What do you mean kick off? you never want your humidity to hit 70%, 60 Max in veg and you're going to want to keep it between 40 and 50% in bloom so again, keep it on all the time, or set it to come on when it hits 60% at the very least

I thought it was a typo. I think he meant "kick on" ... At any rate, I agree about humidity targets. Too wet during flower will lead to issues.

Djdanko23 · Mar 21, 2020

MIGrampaUSA said:
I thought it was a typo. I think he meant "kick on" ... At any rate, I agree about humidity targets. Too wet during flower will lead to issues.

Sorry that us the set point for when the ran starts ramping up. It will slowly increase until it drops below that.

Djdanko23 · Mar 21, 2020

MIGrampaUSA said:
How well can you control your "night time" temperatures? If you keep your low temps to 68-70 degrees, you will have better humidity control.

My inside temps drop pretty low. 60 is my average.

PeaceLuvNblunts · Mar 21, 2020

I always put the inlet pipe sucking straight of the top of dehumidifier.
1) low humidity
2) warms perfect night time temp
Just need a control box or speed regulator to adjust fans....

visajoe1 · Mar 21, 2020

60% humidity isnt too much at all for veg, most likely its too low depending on the temp. VPD charts for reference

Veg chart

Flower chart

MIGrampaUSA · Mar 21, 2020

Djdanko23 said:
My inside temps drop pretty low. 60 is my average.

I bought this: (Click Here) It's worked like a charm.

I have it set to turn the heater on at 69 and off at 76. My cooling fan comes on at 78. It stays with-in those temperatures very nicely.

Reduce Temp drop and high humidity

Djdanko23

MIGrampaUSA

Beachwalker

BurnzYzBudZz

HOWCan.i.helPYOU?

MIGrampaUSA

BurnzYzBudZz

HOWCan.i.helPYOU?

Dirtbag

MIGrampaUSA

Djdanko23

MIGrampaUSA

Beachwalker

MIGrampaUSA

Djdanko23

Djdanko23

PeaceLuvNblunts

visajoe1

MIGrampaUSA

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