Carbon Dioxide In The Greenhouse

Ironically, the greenhouse gas that everyone is worried about these days is usually deficient inside greenhouses. Plants require CO2 for photosynthesis, and in a closed environment, such as a greenhouse, they tend to use it up. For this reason it is important, especially in the Winter, to make sure you have adequate levels of CO2 in your greenhouse. In commercial greenhouses, CO2 levels are supplemented either with propane or natural gas heaters or with tanks of CO2. CO2 is a byproduct of combustion, so venting the heaters inside the greenhouse creates two advantages: heat and CO2. However water vapor is also a byproduct, so venting heaters inside will raise the humidity as well. Greenhouses are often overly humid already. That is why tanks of CO2 are used by many growers.

For the home greenhouse owner, it can be more difficult. A small greenhouse usually does not need a gas heater, and many people don’t want to use artificial heating. Setting a system using CO2 tanks is very expensive on such a small scale. One option is to bring air in from outside, using a heat exchanger to minimize heat loss. If you have the space, putting a compost bin inside your greenhouse can provide some CO2. Some people will use a CO2 type fire extinguisher, spraying it occasionally, inside the greenhouse. An advantage to having a greenhouse attached to your home is that you can open a window or door between them, providing warm air that is high in CO2. Another option for homesteaders with large greenhouses is to keep animals in them. The animals will breathe out enough CO2 to keep the plants happy. Having such an integrated greenhouse is tricky business though. Make sure you know what you are doing, so that the animals, as well as the plants stay healthy.

Another issue with CO2 in the greenhouse is that plants create micro-environments around themselves. If there is no air circulation, they will use up the CO2 close to their leaves and not get any more, even if there is enough in the greenhouse in general. That is one reason why fans are an important part of the greenhouse. Maintaining good air circulation in your greenhouse will improve the health of your plants in many ways.

If you have a well sealed greenhouse, it is imperative that you find a way to supllement the CO2. If you have a fairly leaky greenhouse, you can probably get away with improving the air circulation around the plants.