Quote Originally Posted by louise2308
Thru all of my travels on educating myself on growing I found this tidbit I need to add to this thread....my grow room is a spare room/lg closet and a night when lights go out I close the door....from what I read , if you wait to open the door 30 mins after lights come on.....the plant makes use of the CO2 gathered in the room from the night before...easy and free way of increasing levels...of CO2!!
When you close the door at night it only takes about 2 hours for the plants to use up the oxy and the co2 in your closet. That's why we have fresh air coming in all the time for co2 or add it. Plants need both unless conditions are right.

For plants to use more co2 than is in the atmosphere. Your room needs to be kept at 95 degrees flooded to 1500 ppm's for 4 hours flush with fresh air and flood again. Only during light hours as during the dark it's a waste. only fresh air during dark.

So never just seal a room.

OH, and all that co2 gets you one week off harvest time. Nothing else. no more or less potent or yeild.