Growing in a cold climate

Hi all … I am growing in a very cold winter area … I have to heat the tent 24/7 … not wanting to run the exhaust fan all the time as I have to heat the air too …how do others handle the need to heat the air with the need to bring in fresh … my exhaust fan is set to pump the room out if the temp gets high … do nothing otherwise … using a dehumidifier to keep the humidity within range …have an organic CO2 generator to make up for lack of fresh … please comment as I really need your experience

1 Like

Everybody’s environment and set up varies a little bit. Your lights putting off a heat source. And pulling in fresh air from a controlled environment. Usually balances out with a 10 to 14 degree difference with lights on lights off. I control the temperature from the room I pull the fresh air from. I also Run Exhaust Fan 24/7 to control odor and maintain negative pressure inside tent. Just my thoughts good luck


Generally if you have sufficient airflow to control temp and humidity, then supplemental CO2 won’t be necessary. CO2 is a waste of money and effort for the vast majority of growers as you must maintain higher temps and pour a tremendous amount of light (greater than 1200 PPFD) on your plants’ canopy for them to be able to utilize the higher CO2 levels.

Your lighting and your dehumidifier will both generate plenty of heat, but you may be left with problems during lights out and managing the lower temps. Cannabis tolerates temps between 65 and 85 fairly well. Much below 60 or over 90 isn’t going to work out well for you.

1 Like

We drop to zero at night with rh around 100% at night too … I use a heater in the tent and dehumidifier to keep it at 20degreesc and 60% rh … seems a waste to pump out the conditioned air and suck in cold high humidity air … that’s why I use a co2 bag to top things up


You have the perfect conditions for what is known as a co² burner.

Co² burners create heat as a byproduct of creating co².

So in essence one machine can increase your heat and co2 levels at the same time

There are cheaper ones

I weighed up what an ounce of good pot costs on the street and dicovered its cheaper to heat my own grow and produce my own clean ounce. Also they are safer in a grow enviroment .

I grow 10 x autos a year (Bergmans Gold Leaf Autos)

These oil filled radiators are budget friendly and do the job without any horror show electricity bills.

1 Like

Airflow management. Buy a remote thermostat ($25 on Amazon) and run your fan off of that. Temps rise to a setpoint, fan comes on, vents heat, shuts off, repeat. This is what I do in cold season in the garage.

Thanks TDub … I will track one down in Aus … thanks for reminding me about Lex’s tutorials too … will do more research

1 Like

Thanks Myfriend410 … I have such a fan connected where I can dial in an overheat setting … I use a HLG 550? and do not get much heat from that … considering the cost of electricity in Aus I have been seeking info about the need for fresh air … like running your car aircon on fresh or recirculate

1 Like

Supposed to be a full air exchange every 2 minutes ideally. Real life gets in the way sometimes and usually have a large enough enclosed volume to get away with intermittent air exchange. I added a second, inline 4" that was on it’s own timer and would run periodically through the day, depending on ambient temps. You’ll just have to fiddle with it to get where you want to be. Night hours don’t need as much air too so usually I vent it a couple of times a night if it’s cold out.

Just purchased a CO2 generator and controller … using log … generates heat and CO2 so I don’t need to replace the air in the room constantly as I use a dehumidifier as well … thanks for everyone’s help and advice