concentrations of CO 2 can increase the
growth rate up to 300%. Usually though,
growers report increases of under 100%.
Either way growth rate is increased
significantly. When plants grow faster, it
takes less time to yield a bigger crop. Once
CO 2 enrichment is added to the grow
space, light will most likely be the limiting
factor.
The most practical method that a closet
farmer has to enrich the garden with gas is
a CO 2 tank with a regulator. The regulators
are sold by all of the high-tech garden
supply companies. These devices control
the number of cubic feet of gas released to
the garden. CO 2 gas refills are available
from companies listed under the Bottled
Gas or Industrial Gas sections of the Yellow
Pages. The largest tanks hold 50 pounds of
gas, but they weigh 170 pounds filled. A 20
pound tank is much smaller and weighs
about 50 pounds filled. At room
temperature there are 8.7 cubic feet in a
pound of gas. Refills are inexpensive.
CO 2 enrichment reduces ventilation
requirements considerably for several
reasons. First, the CO 2 in the air is being
replenished and the plants function more
efficiently at a higher temperature when
CO 2 is at high levels. Rather than trying to
draw in CO 2 from the surrounding
atmosphere, the aim is now to stop the gas
from dispersing into it.
Growers figure out how much gas to
use by finding the number of cubic feet (ft^3 )
there are in the grow space (Length x Width
x Height). For instance, a closet 6 feet long,