CO₂ for indoor growing: why carbon dioxide increases growth & yield

Why is Co2 so important for plants?

Plants use CO₂ together with light to generate energy. Without sufficient CO₂, plants cannot reach their full growth potential, even with optimal light and good fertilisation.

CO₂ bags or CO₂ bottle - which is better?

CO₂ bags are ideal for small to medium-sized grow boxes: simple, safe and maintenance-free. CO₂ bottles are suitable for large, professional setups with precise control, but are more expensive and complex.

How much CO₂ is optimal for indoor growing?

The ideal CO₂ value is 800-1,200 ppm. Plants grow faster and achieve higher yields in this range
CO₂ grow bag placed next to tomato plants in a small indoor greenhouse
CO₂ grow bag hanging in an indoor grow tent with LED lighting and cannabis plants
Why is CO₂ so important for growing?

Indoor growing depends on many factors: Light, temperature, humidity - and last but not least CO₂. Although it is often overlooked Carbon dioxide plays a central role in the growth of your plants. Run plants Photosynthesis - They absorb CO₂ from the air and convert it into oxygen with the help of light. This process is the basis for growth, flower formation and yield. The more CO₂ is available, the more efficiently the plant can grow.

In nature, the CO₂ content in the air is around 400 ppm (parts per million). In closed grow boxes, this value can drop quickly - especially at night or with insufficient ventilation. As a result, growth slows down even though there is enough light and nutrients.

CO2 Broccoli Grow Bonsanto
What are the benefits of additional CO₂ supply?

If you specifically increase the CO₂ content in your grow box (e.g. to 800-1,200 ppm), you can:

  • Increase growth rate
    Plants grow faster and stronger - especially in the veggie phase.

  • Increase flower production
    In the flowering phase, a higher CO₂ value can measurably improve the yield.

  • Maximise photosynthetic efficiency
    Light that would otherwise be unused is better utilised - ideal for powerful LED grow lights.

  • Strengthen resilience
    Plants with a good CO₂ supply are more resistant to stress (heat, drying).

When is CO₂ worth growing indoors?

The additional CO₂ supply is particularly worthwhile if your setup is already running at a high level. CO₂ can significantly boost growth and flower formation, especially with strong lighting - for example with LED grow lights over 200 W. Even in well-insulated grow boxes with little fresh air flowing in, a targeted increase in CO₂ makes sense to prevent a deficiency.

However, the prerequisite is that you have already optimised the other growth factors: light intensity, temperature, humidity and nutrient supply should be stable and balanced. This is because CO₂ only acts as a real growth booster if everything else is right.

How do I get CO₂ into my grow box?

There are various methods for the targeted supply of CO₂ in indoor growing - depending on budget, setup and requirements. Particularly precise, but also cost-intensive, is the use of CO₂ bottles with pressure reducer. This professional solution enables precise control of the CO₂ quantity, but is more suitable for larger or automated grows.

CO₂ bags or CO₂ tabs are much easier to use - and ideal for smaller setups. Especially the CO₂ bags from Bonsanto have proven themselves here: They are ready for immediate use, completely maintenance-free and release CO₂ constantly over several weeks - without any technology or electricity. They offer an uncomplicated way to noticeably improve the CO₂ content in small to medium-sized grow boxes.

For experienced growers with professional setups, there are finally CO₂ controller with integrated sensor on. These measure the CO₂ content of the air in real time and control the supply automatically - ideal for completely enclosed rooms with high light output.

And soon even smarter: Bonsanto is currently developing its own CO₂ generator, which is specifically designed for use in grow boxes - compact, safe and perfectly tailored to the needs of modern home growers. This will soon make precise CO₂ control even easier and more efficient.

Important note on safety when using CO₂

Even though CO₂ is a real growth booster for plants, the risks for humans should not be underestimated. In excessive concentrations, carbon dioxide can be harmful to health or even life-threatening - especially in closed rooms without adequate ventilation.

If you are working in a normal room that is regularly ventilated, the use of CO₂ - especially in small quantities and in a 60×60 grow box - is not a problem. Practically harmless.
For safety reasons, we still recommend an inexpensive CO₂ warning device, especially if you use stronger CO₂ sources or are regularly in close proximity to the box.