RH issue mayb?

So basically when my lights are on my RH is staying average around 40 to 50. But at night it boost up almost to 70. Not very cold in my garage and I try to keep it heated. What is causing my RH to go so high at night when my lights are off? Is it because the lights are off and it is cooler or are my plant since they're getting bigger giving off more moisture. I have put in. Container of damp rid to help pull some of the moisture out and I have decent ventilation. I'm not really sure what else I can do other than putting a heater and when the lights go off and keeping the temp up, what are your thoughts?
 

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TintEastwood

Well-Known Member
Be sure to read the Night Cycle section on this write-up. (Applies to non co2 enriched also.)

Just to give you an idea of how theres a lot of stuff going on...



Great primer that helped me.
 
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I just ordered sensi grow a+b should be here tomorrow. Did just have them on Alaska fish .but am changing to the sensi.and I had bud candy in hand for flower.they are on 500 watts of a 1k set up.I do not have ducting and a in line fan yet having to ad as I go .so should I switch to flower and just finish these off before I loose them n start fresh or continterest to grow them out.? I will be letting them sit for 24 hrs then upping to 750 watts for flower provided they can take it .
 

rodclutcher

Member
decent ventilation ...................................you don't even have a real exhaust fan. are you even venting the room your tent is in
 

Dr. Who

Well-Known Member
Run an exhaust fan at night.
Use a speed controller and try it at half speed and adjust up or down as needed from there...
 

thumper60

Well-Known Member
So basically when my lights are on my RH is staying average around 40 to 50. But at night it boost up almost to 70. Not very cold in my garage and I try to keep it heated. What is causing my RH to go so high at night when my lights are off? Is it because the lights are off and it is cooler or are my plant since they're getting bigger giving off more moisture. I have put in. Container of damp rid to help pull some of the moisture out and I have decent ventilation. I'm not really sure what else I can do other than putting a heater and when the lights go off and keeping the temp up, what are your thoughts?
Very simple run a dehuy when lights are out?
 

OldMedUser

Well-Known Member
Humidity is Relative to the temperature hence the name, Relative Humidity or RH. When the lights go out the temp goes down so your humidity is 'relatively' higher at the lower temp. Still the same amount of water in the air but now with the lower temp it reads higher on meters as it's a higher percentage of the amount of water the air can hold at that temp.

Quick note: RH refers to the amount of moisture in the air relative to how much it can hold at a certain temp. So if it says 50% at 70F and you raised the temp 10 degrees but no more moisture was added then the percent would be lower as warmer air can hold more water. Drop it 10 degrees and it will read higher as colder air holds less water.

If the RH goes over 100% then water drops out of the air causing dew. That's known as the Dew Point.
 
decent ventilation ...................................you don't even have a real exhaust fan. are you even venting the room your tent is in
There is a 6inch going out that's not seen in the pic.the big fan helps alot but I found the issue was with garage temp was causing he rh build up sincell it was 73 in my grow and 40 50s in the garage.it's vented every day cause it's my garage.plants are turned every days as well 1/4 turn
 

PadawanWarrior

Well-Known Member
Humidity is Relative to the temperature hence the name, Relative Humidity or RH. When the lights go out the temp goes down so your humidity is 'relatively' higher at the lower temp. Still the same amount of water in the air but now with the lower temp it reads higher on meters as it's a higher percentage of the amount of water the air can hold at that temp.

Quick note: RH refers to the amount of moisture in the air relative to how much it can hold at a certain temp. So if it says 50% at 70F and you raised the temp 10 degrees but no more moisture was added then the percent would be lower as warmer air can hold more water. Drop it 10 degrees and it will read higher as colder air holds less water.

If the RH goes over 100% then water drops out of the air causing dew. That's known as the Dew Point.
Thanks, I couldn't have explained it better.
 
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