02-04-2009, 09:54 PM | || | Join Date: Jan 2009 CO2 is one of
the by-products of combustion. Any hydrocarbon fuel can be
burned to produce CO2, except for those containing sulfur
dioxide and ethylene which can be harmful to plants. You can use
dry ice. Two pounds of dry ice will raise the CO2 level in a
10-by-10 grow room to about 2000 ppm for 24 hours. Fermentations
is another way to add CO2 to small grow rooms if you can handle
the smell. Use a one gallon plastic milk jug and mix one cup of
sugar and a packet of brewers yeast with about three quarts of
warm water. This concoction is changed one to four times daily
as needed. Half of the solution is poured out, then 1 1/2 quarts
of water and another cup of sugar are added. Add more yeast if
needed.