Co2 Systems

so i am playing around with a homemade Co2 generator, my grw room is maybe 8x5.5x3.5ft the most i plan on growing is 4 plants, do i need to worry about inducing Co2 to my plants, most of the systems seem expensive, and or it seems like a 20lb tank wouldnt last long or do they? was just wondering if this is something i should look at adding eventually.

i think if you have good enough ventilation you wouldn't have to have it but i read a while back on a cheap way to produce co2 using yeast or sumthin. might be sumthin for you to look into. me personally i have roughly a 10X10X9 room and just a vortex fan pumpin 740 cfm into my room and my plants r doin great. hope i helped
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found the link ---------> http://www.ehow.com/how_4710564_make-generator-greenhousegrow-room-plants.html

thanks for your reply, yeah i dont think i have to worry about myself either was just curious. i'm using the baking soda method just to see what it does, prolly going to try maybe 2ice. wow that was an awesome link for that, screw the vinegar method, was worried about using that since our plants dont like vinegar to being with or the fumes from what've read. awesome link otw to the store to get some yeast, thx again.