- Carbon dioxide is essential for the growth, development, and health of plant life
- More CO2 means better harvests with the same water and light amounts
- How much CO2 do plants need and how much is too much for us?
- CO2 generators help plants and growers, but too much is too much for plants too
- The greenhouse effect helps plants but hurts humans and the world
Carbon dioxide is essential for the growth, development, and health of plant life
For a while now, many activists have talked about the issue of climate change and CO2 emissions. However, carbon dioxide and indoor agriculture are essential components. It is part of the process by which plants manage their food.
Plants need carbon dioxide (CO2) to survive and grow. It’s a key part of photosynthesis, where plants turn CO2, water, and nutrients into food (glucose) and release oxygen. This glucose fuels the plant’s growth, helping it develop stronger roots, bigger leaves, and more flowers or fruits[1].
But CO2 doesn’t just help with food production. It also controls tiny openings on the plant’s leaves called stomata. These openings allow plants to "breathe" by taking in CO2 and releasing oxygen. When there’s not enough CO2 in the air, the stomata open wider to capture more of it.
On the other hand, if CO2 levels are high, the stomata close slightly, helping the plant save water. CO2 is essential for plants to grow, stay healthy, and thrive, but the world is worried about too much of.
More CO2 means better harvests with the same water and light amounts
Adding extra CO2 to indoor gardens or greenhouses can greatly benefit plant growth. Since indoor spaces can have lower CO2 levels, boosting it can make a noticeable difference. Here are the key ways CO2 helps plants grow better:
- Faster Growth and Bigger Harvests
More CO2 means plants can do photosynthesis more effectively. This allows them to create more food-glucose, leading to faster growth and larger harvests. Plants can grow bigger and produce more with the same amount of light and water. - More Efficient Photosynthesis
With higher CO2 levels, plants don’t have to work as hard to produce food. This makes photosynthesis more efficient, letting them use sunlight more effectively. As a result, plants can grow faster and healthier. - Better Water Use
When CO2 levels are higher, plants don’t need to keep their stomata open as long. This helps them lose less water through their leaves, meaning they can grow just as well with less water. This is especially useful in places where water is scarce. - Improved Nutrient Absorption
With the right amount of CO2, plants can better absorb and use nutrients from the soil. This means they get more value from the same amount of fertilizer, leading to stronger, healthier plants. - Greater Resistance to Pests and Diseases
Some studies suggest that plants exposed to higher CO2 levels may become more resistant to pests and diseases. This could mean fewer losses from insects or plant illnesses. - Shorter Crop Cycles
Higher CO2 can speed up how quickly plants grow and mature. Crops can reach harvest size faster, allowing growers to produce more harvests in a year. This means more food in less time.
How much CO2 do plants need and how much is too much for us?
Carbon dioxide (CO₂) plays a vital role in plant growth, serving as a key input for photosynthesis. But how much CO2 do plants really need, and at what point does it become harmful for plants and humans?
The world is afraid of this greenhouse effect that plants thrive on. We need clean air to live, but we need plants to survive, too. The balance is essential for greenhouse growers and those managing air quality. How can we manage that without cutting certain industries out?
Most crops thrive when CO₂ levels are higher than the natural concentration found in air, which is about 400 parts per million (ppm). Research shows that as CO2 levels increase from 400 ppm to around 1,000–1,300 ppm, photosynthesis rates can increase by up to 50%. This boost in photosynthesis leads to faster growth and shorter cropping times[2].
Greenhouse-grown vegetables like tomatoes, cucumbers, and lettuce benefit the most from CO₂ supplementation. They mature earlier, produce larger yields, and experience an average productivity increase of 20–50%. Similarly, the U.S. Department of Agriculture reported that flowers and ornamental plants show enhanced growth, faster rooting, and taller plants.
However, the optimal amount of CO₂ required for plants depends on several factors, including:
- Type of crop
- Light intensity
- Temperature
- Ventilation levels
- The growth stage of the crop
- The economic viability of supplementation.
While increasing CO2 levels is beneficial, photosynthesis's "saturation point" is typically reached at 1,000–1,300 ppm under ideal conditions. Beyond this range, the gains in photosynthesis and crop growth diminish.
CO2 generators help plants and growers, but too much is too much for plants too
CO₂ levels can drop below 400 ppm in indoor greenhouses, especially when ventilation is limited. This reduction in CO₂ can negatively impact plant growth as photosynthesis becomes less efficient. Ventilation systems can restore CO₂ levels closer to the ambient 400 ppm, but they rarely achieve full restoration. Therefore, many growers supplement CO2 to ensure optimal crop growth conditions[3].
This supplementation with carbon dioxide is possible with products like generators and temporary fixes. Amazon and other websites offer indoor growing products. Those can cost you from 20 dollars a bag to even 1500 dollars for a machine that generates CO2 continuously all the time[4].
People use these things to get better harvests, but you cannot isolate how much CO2 from your greenhouse comes into the atmosphere. At the same time, many experts have critiqued farming and other industries regarding the emission of CO2.
All of this sounds like a double standard and creates more questions. However, not only do humans suffer when there is too much CO2, but plants can also get too much of it. While it’s true that plants benefit from higher CO2 levels, there is a limit to how much they can tolerate.
When CO₂ levels become too high, typically above 10,000 ppm, plants can experience CO2 toxicity. This toxicity can lead to severe damage, as stomata may close to prevent further CO2 absorption. This closure disrupts the plant’s water and nutrient intake, leading to "water stress." The reduction in water absorption slows down growth and can reduce overall yield.
High levels of CO₂ can also hinder photosynthesis. While it may seem counterintuitive, excessive CO2 reduces the plant's ability to convert sunlight into energy. As the stomata close, water loss is reduced, but so is the intake of vital nutrients.
The greenhouse effect helps plants but hurts humans and the world
While plants can tolerate higher CO₂ levels than humans, air quality becomes a concern when carbon dioxide levels exceed certain thresholds. CO2 exposure at 1,000 ppm may cause mild symptoms like drowsiness or reduced cognitive function in humans.
Prolonged exposure to 2,000–5,000 ppm can lead to headaches, dizziness, and shortness of breath. Above 40,000 ppm, CO₂ becomes life-threatening, as oxygen displacement can result in asphyxiation.
To achieve maximum crop yields while ensuring a safe environment for workers and growers, CO₂ levels must be carefully monitored. It is because of the negative effect on both plants and humans tending to them.
For humans, air quality should remain within safe exposure limits, typically below 1,000 ppm, to avoid cognitive effects or health issues. Greenhouse operators and indoor growers should use CO2 monitoring systems to keep levels within the optimal range. Proper ventilation, air exchange, and CO₂ supplementation help maintain a balance supporting plant growth and human safety.
It seems counterintuitive to increase the level of CO2 in your greenhouse so your indoor plants can grow in better conditions but attack farmers for having too many "farting" cows. It is like crying over the lack of greenery and forests while cutting down trees for paper and making space for housing and other buildings.
However, the problem is not carbon dioxide but the amount in the atmosphere. The CO2 cycle is balanced under natural conditions, but human activities (industry, transport, agriculture) have upset this balance. Still, generators and industries that are responsible for CO2 emissions are only adding to the problem.
In the case of agriculture, it is not CO2 itself that is the focus of attention, but methane (CH₄), which is a much more potent greenhouse gas. Livestock (especially cattle) is the main source of methane. In addition, some blame agriculture for land use change (like deforestation) and soil emissions.
Countries have even started to look for particular solutions to reduce methane emissions. The question is whether the feed additives and other products will become another burden for small farmers to remain competitive in the market and still save the planet.
Thus, while CO2 is essential for plant growth, too much of it in the atmosphere hurts the climate. This is why the focus is not only on CO₂ emissions from industries but also from the agricultural sector. It is the vicious cycle of good and bad intertwining.
