Tent temperatures when freezing outside

[PacificNorthWest]

Looking to the crowd for some input.

I currently have my lights turning on at 5pm (off at 5am). I dreamed this schedule up because it's starting to get cold in the Pacific North West.

Anyway, I pull outside air to my basement 4x4 flower tent with a pretty high cfm fan. So far (spring/summer/fall) this has worked great. But I imagine if the temps outside drop below zero, this will be bad for my flowering ladies even if 630 watts of CMH is pumping in the tent...Do you guys agree with this? I'm thinking 20 degrees at the canopy and near freezing in the root zone (where the intake is) could be a pretty detrimental thing?

During the winter... temps during the day rarely go below freezing...but at night they can and do. Anyone around here (B.C.) fine with lights on at night, off during the day when pulling air from directly outside in a PNW winter? Or should I forfeit pulling outside air into my tent for the winter months and just grab basement air?

Just blabbing here...Any hints from anyone?

 

[Herby Paisley]

Hi PacificNorthWest I live on the other side of Canada and our winters get pretty cold and when that happens I just pull air from the basement where I keep my tent Instead of pulling the air from outside like in the warmer months, plus I keep the room where the tent is a lil cooler then rest of house so tent air remains cool going in. Then I just exhaust out the window like usual. Have had no issues so far with this method.

 

[bobrown14]

On those cold cold days I used to just pull from inside then switch back to outside air during warmer days. The cooler temps make for pretty flowers so there's that bonus too.

 

[PacificNorthWest]

On those cold cold days I used to just pull from inside then switch back to outside air during warmer days. The cooler temps make for pretty flowers so there's that bonus too.

Yeah I think what I'm going to do is run a diverter line in my intake hose with a quick flip option. So I can simply close the window when its freezing outside and flip a damper to suck from the basement air.

Can't believe I didn't think of that one when I installed all this in the spring.

Cheers guys!

 

[TorturedSoul]

Yeah I think what I'm going to do is run a diverter line in my intake hose with a quick flip option. So I can simply close the window when its freezing outside and flip a damper to suck from the basement air.

Probably be a big plus to get 3.412 BTU/watt of "free" heat in your basement in the Winter, too.

 

[PacificNorthWest]

I'm afraid the passive exhaust will still have to go outside (fan is on the intake side).

This house stinks of sweet flower enough as it is.

 

[TorturedSoul]

You'll be pulling air from outside then, it'll just come through some other hole. (Air has to come in before it can go out .)

I guess you don't run a carbon filter. Must be a "legal thing," lol.

 

[PacificNorthWest]

 

[Finnicki]

We had out basement insulated two years ago. I have never pulled air in from outside. I use a carbon filter. Smell remains in tent and in that room only. Don’t want to see what cold air would do to the ladies. Guud lukk.

 

[Weaselcracker]

Yeah I’m in PNW BC too and run in the same way. HID lights on at night and shut off around 6 am. My winter temps are not always below freezing but definitely are a lot of the time. My passive intake vent is down low at pot level and blasts them with cool air that sucks in when the fan comes on.

My out-vent fan is run through a simple inline thermostat- so it kicks in to vent the air when temps get up to the high 20’s C/ 80°F-ish or whatever I have it set to. The grow lights heat the grow very easily during lights on.

During lights out there isn’t much reason for the fan to come on. You do not need to be bringing in fresh air during lights out.


My grow room is insulated and retains warmth fine during lights out even in cold snaps.
Having said that in recent years I’ve put in a dehumidifier to run on a timer during lights out- and this does warm things up a bit.

Weather here doesn’t usually ever get below about minus 10°C/ 14°F, and not for very long stretches. If it was twenty to forty below or colder I’d worry more. But then the fan wouldn’t come on much, if at all.