Maximum Yield USA 2015 April | Page 84

sourcing co2 CO2 Natural Gas When they are burned, natural gas, propane and liquid fuels give off carbon dioxide, and there are specialized carbon dioxide-generating burners designed for this purpose. These are most commonly used in large greenhouses and are less suitable for small indoor gardens. These burners are a heat source as well, which must be taken into account when planning your garden’s cooling requirements. Since there are inherent dangers in their use, such as flames and fuel in an enclosed space, I do not recommend their use in home gardens. Compressed T anks Compressed CO2 tanks come with a regulator that allows the gas to be slowly released over an extended period of time. Tanks of compressed carbon dioxide are available at many hydroponics stores and traditional commercial outlets. They are a popular in home indoor gardens, but tanks must be routinely brought in and out of the garden, which may be cumbersome compared to other options. “Supplemental CO2 i