Question about grow cabinet and c02

I am going to build a grow cabinet with dimensions of 4' X 4' X 6'. I need to know if you use c02 can the cabinet be completely 'air tight?' Or would you still need intake and exhaust?

Plants need air to breathe. I'm not too sure where you were going with this or what you meant. But ideally if you want to use co2, then you want an airtight room so your expensive gas doesn't just leak out. But your still gonna need to exchange the air inside the cabinet somehow.

I want to grow in a building outside. It's pretty cold out where I'm at and i'll have a hard time trying to keep the room warm if cold air comes in and out. So If I use co2 in the building is there a need to have an intake and exhaust of the air?

I take that back. I was in a hydro shop this weekend, and they said that if you are supplementing co2 in an airtight room, then you don't need to have fresh air coming in. They said that maybe you could exchange the air for a few minutes every day.

FDD is prolly your man for this one..
As far as i remember, CO2 is generally used when temps are too high, like in the late 80s+, so you may not really need it.
I've grown outside in winter using a shed before now with a small pc intake and exhaust which were controlled using a Rheostat, and used a kerosene/paraffin lantern/greenhouse heater to keep the temps around 60-65, and it gives off CO2 as it burns...The fuel is cheap as hell and one fill of the lantern/heater lasts around 8-9 days.
With lights on the temps were approx 75.
The bud didnt taste of kerosene or anything, neither do my winter veg's that live in the other G-house.

Plants still need plenty of fresh air, even with CO2. You absolutely still need an intake and exhaust.

The deal with being air tight is when you use CO2, you don't just want to send it out into the room and waste it - you want the plants to soak in it. The way my cab works is when the lights are on - no exhaust fans run and I release CO for 30 minutes. The fan on my sealed light hood still runs though - otherwise the cab would heat up terribly. Then the CO2 shuts off and exhaust fans then vent the cab for 30 minutes and then the exhaust fans shut off and CO2 releases again for 30 minutes and we repeat the cycle. My vent fan runs constant during lights out. Just a simple matter of setting two timers up to work together.

My advice? If this is your first grow forget the CO2 and worry about getting everything dialed in and then think about CO2 for a later grow.

Thanks for the advice. This is my 3rd grow and i'm still learning everything. My main wory about growing in a building was the temperature and oxygen in the air. I just felt like with air coming in and out it wouldn't stay warm enough for the plants. So I though that I could do away with the intake and exhaust but I guess it's clear I can't.

frostythesnowthug said:

As far as i remember, CO2 is generally used when temps are too high,

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co2 is what the plant takes in through the stomata and aides in the photosynthesis process...when plants take in air thorugh their leaves they process the co2 and release pure o2 in the air...this is why the air smells fresher and it is easier to breath in the woods or country than in citys

lol. i meant that alot of people tend to use additional CO2 when temps are in too high in the grow space, as high temps effect plants ability to respire sufficiently..
But bein as he's growing in a shed and his area has a cold climate at the moment, i doubt his temps are gonna get into the late 80's - 90+s unless he's using High wattage lighting..
Possibly quite the opposite, and the environment may be on the cold side, hence why i suggested a greenhouse heater maybe a better method of co2 delivery, coupled with adequate intake /exhaust.

have a fun day folks..

frosty

found this on the net:

When using CO2 it is difficult to maintain optimum levels in a grow area employing an air intake. For this reason, it is important that the room be a 'closed' system. Oxygen tends to push additional CO2 out of a room, and since oxygen is created by plants, it is only necessary to vent in order to lower temp and humidity levels within the space


apparently it's not neccessary to have an intake of air but you must have an exhaust. answers my question.

gardenman said:

found this on the net:

When using CO2 it is difficult to maintain optimum levels in a grow area employing an air intake. For this reason, it is important that the room be a 'closed' system. Oxygen tends to push additional CO2 out of a room, and since oxygen is created by plants, it is only necessary to vent in order to lower temp and humidity levels within the space


apparently it's not neccessary to have an intake of air but you must have an exhaust. answers my question.

Click to expand...

If you don't intake there is nothing to exhaust. "Vent" means the process of intaking and exhausting.