Venting C02 when the plants are sleeping?

Justin Freidman

Well-Known Member
Hey Guys,

I'm just about to do my first C02 grow. I have a nearly completely sealed room that has a carbon filtered exhaust system (with non-return valve so when fan is off it's quite sealed) on a timer.

I'm running a Sentinel monitor and doser connected to a solenoid on a large C02 bottle. I have an unlimited supply of C02.

I was wondering if it's good practice to vent the room when the lights and C02 are off? This means the room gets a change of air each day.

Thanks,
J.
 
As far as I know plants do not use CO2 at night, CO2 is used in the photosynthesis process. Maybe someone else can chime in with a better answer

"Photosynthesis is the process by which plants, some bacteria and some protistansuse the energy from sunlight to produce glucose from carbon dioxide and water."
 

fearnoevil

Well-Known Member
Hey Guys,

I'm just about to do my first C02 grow. I have a nearly completely sealed room that has a carbon filtered exhaust system (with non-return valve so when fan is off it's quite sealed) on a timer.

I'm running a Sentinel monitor and doser connected to a solenoid on a large C02 bottle. I have an unlimited supply of C02.

I was wondering if it's good practice to vent the room when the lights and C02 are off? This means the room gets a change of air each day.

Thanks,
J.
No need to change the air, if you're adding the correct amount to meet the ppm you want, then your plants should use it up and, while they may not need it at night, they will the next morning. From what I've read you don't want to go over that 1500ppm, and unless your room is dialed in perfectly (including higher temps and RH) then it's likely they won't even be able to use that much. 1200-1000 ppm is what I hear as optimal - do you have a CO2 meter to help you track that? Also, if it's not prying, how the hell do you have access to "an unlimited supply" of CO2, do you live next door to an Airgas factory, lol?
 

Justin Freidman

Well-Known Member
I'm running C02 at 1000ppm using a Sentinel C02 controller with bottled C02. Plants are in veg at the moment with RH% at 80. Canopy temp is 29 degrees C. Plants are doing great.

I'm playing with autos at the moment and they're on 20/4 light cycle. When it goes dark I vent the entire room for 5 minutes which drops the ppm back down to 300. When lights come back on the room is gassed up back to 1000pm. It literally takes a tiny couple of squirts from the controller to do this.
 
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