CO2 enrichment is the process of increasing the amount of carbon dioxide to a level higher than what is normally in fresh air.
Higher levels of CO2 than normal in air can be caused by human or animal respiration in an enclosed area, by natural off-gassing of CO2 from the ground, or by combustion or compressed CO2 gas.
What makes CO2 enrichment unique is that it is purposely done by indoor growers or in greenhouses to increase plant growth, flowering and to speed the time to harvest.
What is meant by CO2 enrichment?
Fresh air typically contains approximately 400-450 ppm (parts per million) or 0.04% carbon dioxide by volume. Raising the CO2 level to anything above this is considered CO2 enrichment.
How do you enrich CO2?
Air can be enriched with CO2 naturally or artificially.
1. Respiration
Humans and animal respiration is the process of taking in oxygen and breathing out CO2. If they are in an enclosed area like a car or a room, after a few minutes the CO2 in their breath will cause the carbon dioxide levels to rise relative to the oxygen level.
2. Off-Gassing
When CO2 from the soil leaves the ground, it naturally mixes with the air. Because CO2 is heavier than air, in extreme circumstances the CO2 can pool in a tunnel, hole or valley and create a pocket of potentially dangerous levels of CO2.
3. Artificial Enrichment
Plant growers can artificially increase the CO2 level in indoor greenhouses or grow rooms by adding CO2 from compressed tanks or cylinders of the gas. In small grow rooms, this can be accomplished by adding bags of organic matter or fermenting buckets that continuously off-gas CO2. Large commercial greenhouses may use CO2 generators or natural gas burners that give off CO2 as a byproduct of combustion.
Can CO2 enrichment be beneficial to plant growth?
All other factors being the same, plants will grow faster as the CO2 level increases. Plants grow naturally at 400 ppm (0.04% by volume) of CO2. Research shows that doubling or tripling the amount of CO2 (800-1,200 ppm) available to plants during the daylight growing cycle will increase growth 40-100% depending on the plant species.
However, as additional CO2 is added beyond about 1,200 ppm the benefits decrease. Increasing the CO2 level to 4x or 5x normal will result in little to no change. At 2,000 ppm and above, too much CO2 may cause plant damage.
Benefits of CO2 enrichment for plant growth
Enriching your plants with CO2 can lead to substantial benefits, particularly in controlled indoor grow environments. One of the primary advantages is accelerated plant growth and improved yields. CO2 is an essential component of photosynthesis—the process by which plants convert light energy into chemical energy. By increasing the CO2 levels in a grow room to an optimal range of 1,000-1,500 ppm, plants can photosynthesize more efficiently, leading to faster growth, stronger plant structures, and an overall increase in crop production.
In addition to enhanced growth, CO2 enrichment can also improve plant resilience. Higher CO2 levels can enable plants to better manage environmental stress, such as temperature fluctuations or high light intensity. This resilience means plants are less likely to experience growth stalls or nutrient deficiencies, leading to healthier and more robust plants. For growers aiming to maximize their space and production potential, CO2 enrichment is a proven method to boost plant performance and harvest quality.
How do I increase CO2 in my grow tent?
The three most common methods of increasing the level of CO2 in a grow tent are
- Fermentation buckets
- CO2 bags
- Piping in CO2 from compressed gas cylinders.
The advantages of fermentation buckets, decomposing organic matter or CO2 bags is that they are inexpensive. The disadvantage is that over time they lose effectiveness and must be replaced or replenished. In addition, you cannot regulate the exact amount of CO2 being delivered to your plants beyond adding more bags or buckets. However, given their low cost many new growers start with CO2 bags or buckets and a low-cost CO2 monitor.
For many modern growers, tanks of compressed CO2 gas are a preferred option. While the initial start-up cost can be a few hundred dollars for the CO2 controller, tank, regulator, and distribution tubes.
Does adding CO2 increase yield?
There are many benefits to increasing CO2 beyond yield.
- Increased growth and plant size.
- Plants mature faster resulting in faster harvests.
- Faster maturity saves energy and fertilization costs per harvest.
- Increase in the number and size of flowers.
- Reduction in transpiration and increases water use efficiency.
How to Implement CO2 Enrichment to Your Grow Room
Implementing CO2 enrichment in your grow room involves a few strategic steps to ensure effective results.
Step 1. Start by assessing your grow room's current setup, including ventilation, lighting, and plant density, as these factors influence CO2 utilization.
Step 2. Once you’ve mapped out your space, choose an appropriate CO2 source such as CO2 tanks or a CO2 generator, based on the size of the room and the desired enrichment level.
Step 3. Next, install a CO2 controller to monitor and regulate CO2 levels accurately. Position the CO2 release mechanism above the plants, as CO2 is heavier than air and will naturally fall.
Step 4. Connect the CO2 source to the controller, setting the target ppm (parts per million) level according to your plants’ needs—usually between 1,000 and 1,500 ppm for optimal growth.
Step 5. Integrate fans to distribute the CO2 evenly and avoid gas pockets. Lastly, synchronize CO2 enrichment with the grow room's light cycle, as plants absorb CO2 most efficiently during photosynthesis.
Regularly monitor and adjust the system to maintain consistent, beneficial CO2 levels for healthy plant development.
CO2 Controller for CO2 Enrichment
CO2 controllers play a pivotal role in optimizing the process of CO2 enrichment within grow rooms. These devices are designed to monitor and regulate CO2 levels precisely, ensuring that plants receive the optimal amount needed for accelerated growth and higher yields. By maintaining CO2 at consistent levels, growers can avoid the common pitfalls of under- or over-enrichment, which can either limit plant growth or lead to wasted resources and potential plant damage.
Implementing CO2 controllers in grow rooms not only streamlines the process but also provides peace of mind with automated adjustments based on real-time CO2 concentration data. This automation allows for efficient management of CO2 without constant manual oversight. Additionally, many modern CO2 controllers come equipped with features such as integrated alarms, customizable settings, and compatibility with environmental monitoring systems, making them an invaluable tool for maximizing productivity in controlled agricultural environments.
For more information, see all our CO2 meters and monitors for agricultural use.