need help on room questions

hello all,

after a while of thinking it over i build i box. the dimensions are 2 feet deep, 3 1/2 feel tall, and 3 1/2 feet wide. the box will be in an cold shop heated to about 50 degrees fahrenheit most of the time, when we go there is will be about 65-70 degrees. my questions are how should i ventilate this box? or can i just completely seal it and put in an mini co2 system? i am thinking about getting an 400 or 600 watt dim-amble ballast or else a 36" 6 lamp HO t5 set-up that puts out roughly 20,000 lumens. i have to box built but i am just wondering what you guys think i should do. the box will be used to VEG ONLY.

Thanks much!!

yo- 50 degrees F seems a little cold to me. You will need a heating system unless you run your lights 24/7. Best way to ventilate the box is to have an air cooled HID reflector/hood pulling air from inside your box, out into the atmosphere. You can use passive intake to keep fresh air coming into the box since it's so small. I don't know if a CO2 system is worthwhile.. but if you have the cash it cant hurt anything. Only thing you will need to do is make sure there is no air leaving the box and instead of using a ventilation system like i just described, pull air from outside box through the air cooled hood and then back outside the box again. That way you will keep all the CO2 inside the box. Just gotta set it up and run it, see what the temperatures are and make adjustments as necessary.

wouldnt it just be best to have the light not air cooled and get some heat from that? that way my little heater would not have to work as hard while the lights are on and such?