Carbon Dioxide CO2 Enrichment in an Indoor Garden

CO2 and the Carbon Cycle

Having an indoor garden will keep a family in fruits and vegetables all year round, even being able to grow things out of season. However, with indoor climates and lighting being different than the outdoors, much of what the Earth manufactures naturally must be recreated for the indoor garden environment.

One of the most important of these is carbon dioxide, a gas with no odor or color that forms when we exhale or when carbon-based fuel is burned. Carbon, present in all organic compounds goes in a cycle of constant reproduction – a cycle we are very much a part of. At the center of each plant, there is the carbon that has been obtained by absorption from the environment.

Every living thing is carbon based, and for vegetation to grow and reach its maximum capacity, a large amount of carbon dioxide (CO2) is needed. It should be monitored closely as not to increase the levels by too much. Ideally, when CO2 is increased in an indoor environment, the temperature should also be warmer.

Controllers for CO2 will regulate temperature as well as CO2 levels. Average levels of CO2 are around 300-400 ppm (parts per million) and for a typical indoor garden the levels should be increased by about 1200 ppm.

Carbon is always on the move, so remember that the plants growing will absorb as much as available, which depletes the levels.

CO2 occurs naturally in the environment, but for an indoor garden, it has to be created, especially in the larger amounts that plants need.

Larger open areas would not benefit as much from added CO2 due to the constant exhaust that would have to be running. However, the sealed atmosphere of an indoor garden, and especially a grow box, would benefit greatly from added CO2.

Plants go through a process called photosynthesis which is when carbon dioxide and water combine and are powered by the sun (or in this case, a grow light) to create necessary carbohydrates.

CO2 injector

One of the simplest and most inexpensive ways is to have a CO2 injector. These injectors have regulators to keep a constant flow of CO2 going into the grow box without exceeding the limits that can cause the environment to become toxic with “greenhouse gasses”. Some have timers installed into them to further regulate the CO2 releases. The temperature should also be monitored to keep the environment warm enough to let the carbon dioxide do its work.

Since it takes a long time for this type of system to produce the CO2, it is better to use this type of system for a smaller indoor garden that can be easily monitored.

Adding CO2 has other benefits as well. When plants are growing, if the CO2 levels are lower, the leaves tend to open up more trying to catch whatever CO2 is available. This in turn, causes water loss.

With added CO2, the plants retain more of the water given, which in turn aids in their ability to withstand drought. This results in a hardy plant full of vegetation. It also improves their ability to withstand toxins in the air as well as environmental stresses such as higher soil and air temperatures.

In short, carbon dioxide is the food that plants need to survive and reproduce.

If a larger indoor growing environment is being considered, investing in a CO2 generator may be the way to go. These run off either a natural gas line or propane.

Natural gas is often used due to the propane tanks needing changed often, which can be time consuming.

Generators also keep the temperature raised to around 85-90 degrees without a separate heating system. Higher temperatures for the growing environment are essential for the added CO2 to achieve its purpose.

CO2 Generator

The old saying “too much of a good thing” is very true when it comes to creating an environment for indoor gardening. While warm and humid temperatures are ideal, too much humidity can make the plants wilt, defeating the purpose. De-humidifiers will keep the relative humidity (RH) levels between 55-65, and thermometers keeping track of the temperatures will advise as to when the levels need increased or decreased.

Adding CO2 in the indoor garden environment will increase the use of water and nitrogen, which in turn will require some space adjustments. This is why it is important to always keep the levels of CO2 regulated and the grow box monitored, so the vegetation doesn’t get too crowded and plants won’t wilt. The levels of CO2 certainly need monitored so they don’t exceed 2000 ppm. This level can be toxic to plants, animals and humans, so to be safe, the levels should be around 1500 ppm.

How Much CO2 Does an Indoor Garden Need?

For an average grow room it can easily be determined how much CO2 needs produced by multiplying the increase of CO2 (1200 ppm or .0012) by the number of cubic feet of the area. Once this number is determined, the gardener knows how much cubic feet of CO2 needs produced per hour. This can be regulated with a digital control timer for the exhaust fan and CO2 emissions where a constant timed flow will be distributed through the indoor garden.

Exhaust fans should be set to turn on at around 85-88 degrees and turn back off when it reaches slightly above room temperature (70-75 degrees). The exhaust fans will keep the area from getting too humid.

If a control valve and a pressure regulator are purchased, the CO2 tank, which contains usually around 1200 psi (pounds per square inch) needs the pressure slowed down to about 100 psi. The regulator is attached to the CO2 tank and then adjusted to the slower rate. After this, the valve needs to be attached to the regulator. On the valve is tubing that will direct the flow of CO2 in the garden. The tubing should be set up in and around the plants so it is evenly dispersed.

Natural Methods to Enrich CO2

Many people prefer completely natural ways of adding the essential nutrients and gasses to an indoor garden.

Some breed mice, hamsters, gerbils, and other small animals to be in the same area of the garden. The constant inhaling of oxygen and exhaling of carbon dioxide will keep the levels increased as well. It will take several of the smaller animals to generate the carbon dioxide needed to keep the levels increased, which in turn depends on the size of the indoor garden or grow box.

Of course, you don’t want the animals running loose through your garden as they will attack the plants. Keeping them in cages where the room is well ventilated and fans blowing the air from the cages into the environment is a natural way to add carbon dioxide to the environment.

Again this needs to be regulated, and several cages with a few mice or other small animal in each one will be needed according to the size of the garden or grow box.

The benefits to using animals as a source of carbon dioxide include being part of the natural carbon cycle. Animals that eat vegetation consume the carbon dioxide that has been used to grow them. The animals in turn exhale healthy carbon dioxide to increase the growth of the plant, which will go on to feed the animal. When the animal dies, it goes back into the ground to nourish the plants with more carbon dioxide. It’s a cycle that has existed for thousands of years and with the right care of the planet will exist for many more.

Written by Angela Sangster, Copyright 2012

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