How to use C02? indoor growing

So my trunk grow set up is kinda pissing me off...i am not getting enough air flow and i have been having to keep the lid open with the fan on..i was wondering how the co2 trick works i never done it!...but some helpful tips would be nice..and how much to use?...how well does it work?...anyways sorry i wish i had pics but i cant find my diggy anywhere

Get a 1l bottle, cut the neck off. Fill it with water, add 1tbs dry yeast and 2tbs sugar and mix. put a plate under it in case it fizzles and runs over. Change every 2 weeks.

This trick works great for small spaces and produces enough co2 for 3-4 big (1,5m) plants. But be careful, co2 can rise the temp by several degrees! I recommend getting 2 fans for best air exchange, 1 bigger for intake, 1 smaller for outtake. This seems to perfectly balance heat and humidity even with co2 rich air.

thanks alot ya the space im doing my trunk growing is a small space which would seem to work well for it..have you used this method alot ?...does it work well?

I use it and it works great. Just don't forget, you don't want the exhaust on all the time, otherwise the CO2 will go right out the door. You want the plants to sit in as much CO2 as possible (up to 1300 PPM) and then flush the entire system of air in about 30 seconds. For instance, in my room I have Exhaust off for 30 min, on for 1 minute, off for 30 minutes, on for 1 min.......etc.

Plants do not use CO2 when the lights are off, so the timing doesn't matter during dark hours.