How important is additional co2?

Originally Posted by Cloudz2600

I would guess that one 2L would be enough for a 3x3. I'm going to go ahead and make 2 of the things for my closet grow. Not like more co2 will hurt em.

3000 ppm and above will kill your plants. 5000 ppm and above will kill YOU. Yeast will never produce anywhere near that tho.

What's a better method of distribution? Hanging it over the plants or having it behind a fan and having the fan do all the work?

Also I realize that with dry and and yeast methods you can't determine how much the ppm is, but is there an average number?

CO2 done correctly can increase yeilds by up to 80%. Thats assuming you keep the co2 at the needed 1500ppm and do correct air exchanges.

Originally Posted by Red1966

3000 ppm and above will kill your plants. 5000 ppm and above will kill YOU. Yeast will never produce anywhere near that tho.

not sure those numbers are right. not trying to start anything but humans don't feel the negative affects of Co2 poisoning until about 8,000ppm i believe. maybe less under LONG term exposure. plants can actually handle much higher levels. well above 10,000ppm; especially under ideal growing conditions.

http://inspectapedia.com/hazmat/CO2gashaz.htm