How important is additional co2?

I found a thread on grasscity(atm I can't search on RIU) that gave a pretty interesting and cheap way to make some co2 for the plants.
http://forum.grasscity.com/indoor-marijuana-growing/110325-co2-has-totaly-turned-my-plants-around-2.html
Doing a 3 plant closet grow right now with just one 12" fan. Is enough co2 getting to my plants and either way, how much of a difference would additional co2 make via this method? The only thing I don't have is the yeast so I figure it'll be a pretty cheap way to help the plant. If one 2L isn't enough I'm guessing adding another wouldn't be too hard.

I use dry ice, as for results look at my grow for evidence. but. I should have a good C02 exchange with your fans

Yea, your grow gave me the idea to look this stuff up. How big is the area you're growing in though? And from what I read dry ice melts pretty fast.

Dry ice is stored in a Styrofoam box suspended over plant since co2 is heavier than air one pound is 4 dollars and last me about a week I don't put it all out at once. MY area is 36x18x18

I'm gonna go ahead and assume that's in inches? So you just put the box over the plant, leave the lid open and walk away?

Yup for the most part but there is a cpu fan inside.
Ps I lay the box on its side either opening is pointed to my plant.

They sell bags on amazon that emit Co2. They claim that a 30 dollar bag can last 6 months, although ive never tried it.

MyndMy said:

Dry ice is stored in a Styrofoam box suspended over plant since co2 is heavier than air one pound is 4 dollars and last me about a week I don't put it all out at once. MY area is 36x18x18

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i do the same method as well but damn 4$ a pound thats expensive. i pay about $1.70 a lb. and it does wonders i tell ya. ive done it with the 2 liter bottle and yeast method too with same results. oh and btw the yeast usually comes in small packs that go for about 10- 25 cents not expensive at all. either one works just fine but the bottle meyhod is much cheaper.

.25 huh well I am a cheap bastard

bestbuds09 said:

i do the same method as well but damn 4$ a pound thats expensive. i pay about $1.70 a lb. and it does wonders i tell ya. ive done it with the 2 liter bottle and yeast method too with same results. oh and btw the yeast usually comes in small packs that go for about 10- 25 cents not expensive at all. either one works just fine but the bottle meyhod is much cheaper.

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Ima have to try that yeast method, what is required to successfully pull it off in a 3x3 tent?

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.

Cloudz2600 said:

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.

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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.

Red1966 said:

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

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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

Bought the packets just now. Was $1.59 for three 1/8 tsp packets.