CO2

We know photosynthesis as the basic process plants need to live. Photosynthesis uses light energy (sunlight and artificial light) to create (synthesise) energy-rich organic compounds - sugars - from simple inorganic substances - carbon dioxide (CO₂) and water.

This means that if plants lack carbon dioxide, they cannot develop as they should. Photosynthesis produces sugars, which act as stores (sources) of energy and building blocks for more complex molecules. As the concentration of CO2 increases, the rate of photosynthesis increases.

Carbon dioxide, naturally present around the leaves of plants growing in the wild and when growing outdoors (outdoor), can be supplied artificially to plants when growing in a tent or room (indoor), because without it they grow only very slowly (by up to 50%!).

In practice, by adding CO₂ we can speed up plant growth by up to 20-30%, shorten the maturation process (the cycle can be shortened by up to two weeks) and increase yield per m². Supplementing carbon dioxide can also improve the quality of the resulting crop; some edible crops may have richer nutritional content, more pronounced aroma or longer shelf life.

The simplest way to add CO₂ is by using effervescent tablets, which gradually dissolve in the nutrient solution, or hanging bags with bacteria or fungi, which we recommend mainly for smaller spaces and hobby growers. Another option is CO₂ dispensers, which you connect to a compressed gas cylinder - they are especially suitable for larger spaces. You can also buy them with a dispenser, valve and sensor in a complete set.

Our range also includes generators of CO₂, used mainly by professionals, because carbon dioxide is produced by combustion, which increases the temperature and can lead to issues such as incomplete gas combustion or dangerous by-products of combustion. New are liquid sources of CO₂, which are added to watering.

Adding CO₂ only makes sense during the day (when the lights are on), because plants do not need it at night at all. At the same time, it is necessary to consider ventilation - you do not want the added CO₂ to be vented out immediately. We recommend interrupting air exchange with a controller that switches the fan off at a certain temperature or humidity, or closing the system completely.

Another factor is temperature - photosynthesis is two to three times more efficient with every 10 °C increase in temperature, and the increase stops around 35-45 °C; for indoor growing we recommend a temperature of around 30 °C if you want to make full use of the added CO₂ .

Do not forget the light intensity. If there is too little light on the plants at the same time, they will also not fully use the added CO₂ and will photosynthesise less due to a lack of light energy. With the opposite problem (too much light), they will also stop photosynthesising. In general, we recommend adding CO₂ if you are already using high-intensity LED light or powerful discharge lamps.

If you want to add CO₂ to the growing space on a large scale, we definitely recommend using a metre. Higher concentrations of CO₂ do not harm plants, but they do affect people. You know it from a stuffy room - headache, reduced concentration, and at really high levels (such as 3000 ppm) you can even lose consciousness.

In practice, you will need to determine the ideal CO₂ concentration for your exact conditions (temperature, natural saturation, humidity, light intensity) and plants (species, variety, genetics) by trial and error. But we can definitely say that it is very likely to be worthwhile thanks to improved growth and higher yields.

Frequently asked questions

By how much does CO₂ increase yield?

Under good conditions (enough light and heat), it speeds up growth by roughly 20-30% and can also shorten the cycle length. Without strong lighting and the right temperature, however, plants will not use CO₂.

What solution should I choose for a small tent?

For hobby growers and smaller spaces, the simplest options are effervescent tablets and hanging bags. They do not need a pressure cylinder or control, and you can start using them straight away.

When should I choose a dispenser for a pressure cylinder?

For larger spaces where you want to maintain a stable concentration. You can also get a dispenser for a CO₂ cylinder in a complete set with a valve and sensor that control dosing automatically.

Is adding CO₂ safe?

Higher concentrations do not harm plants, but they do affect people. When dosing on a large scale, therefore use a metre - at levels around 3000 ppm there is a risk of headache and even loss of consciousness, and do not enter the space with dosing running without checking.

We will be happy to advise you on how to add CO₂. Just contact us at info@higarden.cz.