How to use CO2 in indoor cultivation

carbon dioxide + water + light energy → carbohydrates + oxygen

It is a known fact that when plants appeared and developed on Earth, carbon dioxide (CO2) was at a much higher concentration than it is now. The concentration of CO2 was certainly over 1000 parts per million (ppm). In fact, the average outdoor CO2 concentration is about 400 ppm (depending on your location). Thus, the plants are satisfied and are stimulated by breathing air with a higher concentration of CO2. That is why so many greenhouses enrich with CO2 during photosynthesis to supply plants with this basic building material. Through photosynthesis, carbon in CO2 is extracted and involved in the construction of leaves, stems, flowers and fruits. The right concentration of CO2 from the beginning of growth to fruiting allows for faster ripening and higher yields.

The benefits of CO2 enrichment are that it reduces the time from sowing to harvest, generally accelerating growth and increasing yields. Plants also become more resistant to some pests such as mold. Rutgers University compares lettuce grown outdoors and in a climate-controlled greenhouse enriched with CO2. The results are in favor of greenhouse lettuce. Lettuce grown in the open reaches maturity for the market in 62 days. In the greenhouse with a well-controlled climate and increased CO2, lettuce is ready within 48 days: you earn 14 days. Greenhouse lettuce also weighs 33% more than grown outdoors.


How plants absorb CO2

Plants absorb essential carbon atoms from the air only by breathing through their stomata (The leaves of the plant are covered with hundreds of stomata of 2 square centimeters and allow the plant to breathe CO2, oxygen and absorb water). As soon as they close, the plant is deprived of carbon material - essential for building plant cells. Most of the essential nutrients for plants are obtained through the roots. If one essential ingredient is not in the right ratio with all the others, it could slow down growth. Very often CO2 and the presence of carbon become a limiting factor. Proper air temperature and humidity are a prerequisite for keeping the stomata open at all times to absorb CO2 (photosynthesis) and to exhale excess and waste (in the dark). That is why close to optimal climate control is needed!


How much CO2?

It is well known that the level of CO2 in the air with values ​​of 700 and 900 ppm improves crop development and yield. Most plants grown for their beautiful flowers or leaves grow optimally at 800 parts per million. Roses stand out because they need about 1200 ppm of carbon dioxide concentration for best results. For most fruits and vegetables, the ideal level of CO2 in the garden should be at least between 1,000 and 1,200 parts per million.


Don't overdo it with CO2!

Excessive CO2 concentrations are harmful to plants. Too high a level of CO2 reduces plant transpiration during photosynthesis: without or with less transpiration, the plant absorbs less nutrient solution and slows growth. If the CO2 levels are too high, necrotic spots (dead tissue) appear on the leaves. These dead tissue stains are great food for the development of bacteria and mold.


When and how much CO2?

The recommended concentration of CO2 in a room is between 1000 and 1500 parts per million. There is no benefit for the plant from maintaining higher values, and they are dangerous to humans. It is also a waste of money. Only very few exceptions from the plant world take up CO2 during photosynthesis, and this is the period when there is no light.


Caution, safety tips

Carbon dioxide (CO2) is not toxicin itself. However, the higher the level of CO2, the more difficult human breathing and brain function. People with respiratory problems such as asthma can be affected at the lowest level such as 1000 ppm, while other people they will not feel discomfort. But for dangerously high levels above 6,000 ppm CO2, the inconvenience is completely reversible. The affected party simply has to go to a place where the air has a lower level of CO2, such as outside, until the discomfort disappears and the level of CO2 in the blood decreases.