When it comes to carbon dioxide and indoor agriculture, we know that CO2 is an essential component. In fact, CO2 is part of the process by which plants make their own food. It's during this photosynthesis where plants use carbon dioxide, along with water and nutrients to produce glucose and oxygen. Further, the glucose produced by the photosynthesis is used by the plant as an energy source for growth and development.
In addition to providing a source of carbon for photosynthesis, CO2 also plays a large role in regulating the opening and closing of a plants stomata. It's these tiny pores on the plant leaves that are used for gas exchange. When the concentration of CO2 in the air is low, plants will open their stomata wider to allow more CO2 to enter. And, conversely, when CO2 levels are high, plants will partially close their stomata to conserve water.
It's this carbon dioxide that is truly essential for the overall growth, development, and health of plant life.
What are the benefits of CO2 supplementation on plants?
When it comes to CO2 supplementation it can provide several benefits for plants, particularly in indoor growing environments where concentrations of carbon dioxide can at times be limited.
Below we have highlighted the main benefits of supplementing plants with CO2:
- Increased Growth and Yield: CO2 supplementation can promote increased plant growth by providing a greater source of carbon for photosynthesis. Higher levels of CO2 can also improve the efficiency of photosynthesis, allowing plants to produce more biomass with the same amount of energy.
- Improved Photosynthesis: With higher levels of carbon dioxide, plants can perform photosynthesis more efficiently. In fact, this allows them to better use available light and produce more energy for growth and yield.
- Better tolerance of stress: Plants grown in environments with higher than normal levels of CO2 are able to tolerate environmental stress factors, such as high temperatures, low humidity, and drought.
- Reduced photorespiration: Photorespiration is a process that can limit the efficiency of photosynthesis in plants. Higher levels of CO2 can reduce photorespiration, leading to greater efficiency, productivity, and product.
- Shorter crop cycles: CO2 supplementation can also reduce the time required for crops to mature and reach harvestable size. This can allow for more frequent crop cycles and higher overall yield.
While these five benefits can provide greater capabilities for growers, it is important to also ensure that you are maintaining proper levels to avoid any potential negative effects on the environment and human health.
How much CO2 do plants need?
For the majority of indoor greenhouse crops, net photosynthesis increases as CO2 levels increase from 400 ppm (ambient air levels to 1,000ppm (parts-per-million). Most crops show that for any given level of photosynthetically active radiation (PAR), increasing the CO2 level to between 1,000ppm - 3,000ppm will increase the photosynthesis by about 50% over ambient CO2 levels.
For some crops the economics may not warrant supplementing to 1,000ppm CO2 at low light levels. In terms of overall CO2 implementation, greenhouse-grown vegetables like tomatoes, cucumbers, and lettuce show earlier maturity, larger fruit size, a reduction in cropping time and yields increasing at an average of 20 - 50% with supplemented CO2.
Flowers and ornamental plants however, also show faster growth, more extensive rooting, and greater plant heights shown in a study by the U.S. Department of Agriculture.
During particular times of the year and especially in indoor greenhouses that have reduced air exchange rates, the carbon dioxide levels can easily drop below 400 ppm which has a significant negative effect on the crop. Ventilation during the day can raise the CO2 levels closer to ambient but never back to ambient levels of 400 ppm. Further, the supplementation of carbon dioxide is seen as the only method to overcome this deficiency and increasing the level above 400 ppm is beneficial for most crops.
Overall, while we see the benefits of CO2 supplementation the exact levels to which the CO2 concentration should be raised depends on the crop, light intensity, temperature, ventilation, stage of the crop growth and the economics of the crop. For most crops the saturation point will be reached at about 1,000–1,300 ppm under ideal circumstances. However, every application and environment differs depending upon your overall set-up.
Does the quantity of CO2 in the air affect plant growth?
The quantity of carbon dioxide in the air can affect plant growth in an indoor grow environment or greenhouse. Because CO2 is a key component in photosynthesis, the the CO2 in the air can also have a significant impact on the plants growth and overall development.
While we know that in a typical atmosphere CO2 is around 400 ppm, the optimum concentration of CO2 for plant growth varies on environment but generally falls at 1000ppm-1200ppm.
However, when the concentration of carbon dioxide in the air is lower than the optimal range, plants may experience slower growth rates and reduced yields. Conversely, when the concentration of CO2 is higher than the optimal range, the benefits to plant growth may begin to plateau, and there may even be negative effects on plant development.
Careful monitoring and control of CO2 levels are almost mandatory to ensure a healthy plant growth and safe grow space environment.
Can plants die from breathing in too much carbon dioxide?
Many individuals assume that plants are similar to humans or animals, however, they do have the same respiratory systems so are more unlikely to die from breathing in too much carbon dioxide. Since they use through stomata to intake CO2 they have a more controlled means of intake.
However, excessive levels of carbon dioxide can have negative effects on plant development, as well as on the overall environment. When carbon dioxide levels are too high, the efficiency of photosynthesis can be reduced, leading to a slower growth and reduced yield. The Canadian Agriculture Association states the average CO2 toxicity level for a plant is at 10,000ppm. At this rate photosynthesis would be very low due to the closing of the stomata and the level of CO2 is sufficient to cause a toxic effect on the plant and cause serve damage.
Additionally, excessive levels of carbon dioxide can also cause the stomata on the leaves to close, which can reduce the amount of water and nutrients the plants can absorb resulting in "water stress".
While excessive CO2 is fairly uncommon, it can occur which is why its important to be able to monitor and control your plants CO2 levels to gain the most productive plant yields, productivity, and environment you are looking for.
How do you measure CO2 for plants?
There are many ways to measure the carbon dioxide in your grow space, including devices like CO2 meters, data loggers, and grow controllers.
Below we highlight a few common methods:
- Carbon Dioxide Safety Monitors: a CO2 safety monitor is a device that measures the concentration of CO2 in the air for safety purposes. For those indoor growers using and supplementing CO2 its important that they have a instant indicator should CO2 levels exceed the normal threshold so they do not enter the space and gain potential negative health effects.
- Carbon Dioxide Grow Controllers: A CO2 Grow Controller is commonly used across many indoor greenhouse applications and can measure the concentration of CO2 in the air, display the concentration in ppm, and can be set to trigger other environmental systems based on the CO2 level.
- Carbon Dioxide Data Loggers: A CO2 Data Logger is another device that records environmental data over time. A CO2 data logger can be used to measure and record CO2 levels in any given grow space or over a period of days/weeks/months. This device can be most useful for tracking changes in CO2 levels over time and identifying patterns or trends.
- Manual Testing Kits: Manual testing kits can also be used to measure carbon dioxide in a grow space by taking air samples and analyzing them using chemical reagents. These kits are typically less precise than CO2 monitors, controllers, or safety alarms; but can be useful for spot checking.
5 Tips for Properly Supplementing Plants with CO2
When measuring CO2 levels in a grow space, it's important to take into account factors such as room size, ventilation, air flow, and the number of plants being grown. While carbon dioxide levels can vary widely depending on these factors, it's important to monitor and adjust environmental conditions as needed to maintain optimal CO2 levels.
Below we highlight a few additional tips for supplementing CO2 in your space:
- Have the right light - the rule of thumb: 7500-10,000 lumens per sq. foot will allow for the full benefits of CO2 enrichment at 800-1,500ppm.
- Seal the space - prevents CO2 from leaking out and will maintain your CO2 levels.
- Temperature - many growers recommend between 85°F and 95°F for CO2 to be the most beneficial.
- Adequate Air Flow - For the best results, have your HVAC system move air and CO2 from the floor level to distribute the gas evenly across the space. Or, direct a fan upwards from floor level to keep CO2 circulating and evenly dispersed and efficiently over the crop.
- Rest - Your plants don't take in CO2 when the lights are off, so don't waste valuable Carbon Dioxide when the plants are "sleeping". Use a controller with a light sensor embedded.
CO2 Grow Controller Solutions
When it comes to cultivation and indoor growing, CO2 grow controllers can often be one of the best tools for maintaining optimal CO2 levels in the growing environment, which can help to increase plant growth, yield, and overall quality.
The RAD-0502 CO2 Controller is just one example of a CO2 grow controller that is commonly used in the field to provide a simple and affordable way to adjust and review your CO2 levels uniquely for your grow environment.
These devices can also help maintain optimal CO2 levels in the growing environment by automatically adjusting the amount of CO2 being released into the air so you can ensure that your plants never exhaust their supply of CO2 and grow at their maximum potential under optimized conditions.
Additionally, CO2 grow controllers can also be useful in controlling other aspects such as temperature, relative humidity, and lighting. By integrating CO2 controllers, growers can create a more precise and efficient grow space to maximize plant yields, quality, and productivity.
These devices can also be used not only in greenhouses, but also grow rooms, hydroponic shops, mushroom farms, or anywhere elevated CO2 levels are used to maximize plant growth.
Are you looking for more information in regards to agriculture CO2 solutions? Let our CO2Meter experts help educate you about devices for your application. Contact us today.