The Benefits of Adding CO2 to your Grow Room

CO2 is a fundamental building block for plant growth and is often taken for granted because of its abundance in the atmosphere. Because CO2 is such a crucial element of photosynthesis, not only is it something that you simply can’t do without, but it’s also something that can be effectively utilised to increase growth rates and, by extension, yield.

How does CO2 work?

Most of us know that humans and animals inhale oxygen and exhale carbon dioxide - which is absorbed by plants. But do we know why plants need carbon dioxide?

Carbon dioxide is an important element in photosynthesis, which is a process that converts energy from sunlight to chemical energy stored in carbohydrates (glucose). It's important for photosynthesis because it provides the carbon required for the plant to produce glucose, which is used to complete cellular processes in the plant. These cellular processes enable the plants to develop seeds, grow leaves, make fruit, and form flowers.

During photosynthesis, plants gather carbon dioxide from the air and water from the root zone. They then convert this carbon dioxide into glucose and the water into oxygen. Inside the plant cell there is a light-absorbing pigment called chlorophyll, which has the role of absorbing blue, red, and (to a lesser extent) green light waves from sunlight. Because less green light is absorbed (and thus reflected) by plant cells, plants appear green in colour to the human eye. Chlorophyll essentially allows the plant to absorb the energy needed to complete the photosynthetic process.

The process of photosynthesis is often written as the following chemical formula:
This means that six molecules of carbon dioxide (CO2) react with six molecules of water (H2O) to form glucose molecules and oxygen. These glucose molecules are then stored in the plant (such as in leaves, stems, fruits etc) while the oxygen is released through pores on the leaf and through the roots.

How is this relevant to my grow?

Because CO2 is such a fundamental driver of plant metabolism, not only will adequate atmospheric CO2 levels help to ensure happy, healthy plants; but it’s possible to supercharge growth beyond usual rates by providing additional CO2 to your plants – increasing vigour, speeding up flowering/fruiting and increasing yields. Most growers agree that you will get about 20-30% more yield, with an increased growing speed of at least 15%, by adding CO2 to your grow room.

What CO2 levels are best?

Average atmospheric levels of CO2 are currently around 415ppm (parts per million) and on the increase. However, this is still quite far from the levels required for optimal growth, which is around 1200ppm. Growth rates can still be increased beyond this, however, it is important to balance the costs of increased CO2 with the benefits gained in yield; increase levels beyond 1200ppm and you may start to reach a point of diminishing returns.

Bear in mind that because CO2 is just one of the fundamental inputs required for plant growth, other inputs (such as water, light intensity, nutrients, temperature and humidity) should be increased in proportion with CO2 in order to maximally benefit from the growth potential that comes with extra CO2. While simply increasing CO2 in your grow room from a baseline of 415ppm will improve growth rates, your plant will be left wanting more of everything else and will have under-utilised growth potential. Too much CO2 in your grow room can also be detrimental to your plants, so care should be taken to ensure that whatever you’re using to distribute extra CO2, it is appropriately matched to the size of your grow room.

How do I increase CO2 availability to my plants?

There are a few different CO2 products on the market to suit the grower, depending on the size required and the budget. Let's go through some of the popular choices currently used by growers today, starting from the cheapest through to the most sophisticated. It is important to note that in order to get maximum benefit from supplemental CO2, growers should reduce external extraction as much as possible. Creating a ‘closed-loop’, sealed room environment will ensure that CO2 isn’t wasted by being taken away from the growing area before plants have had a chance to use it.

Exhale Organic CO2 Generator

Arguably the simplest and most user-friendly CO2 generating product out there, the Exhale Organic CO2 Generator utilises the natural aerobic respiration process of the Mycelium contained within each bag and will provide a boost of CO2 for up to 6 plants, and for up to 6 months. The low cost, flexibility and ease of use of this product makes it a fantastic option for hobby growers or - when multiple bags are used - for larger-scale growers who don't want much fuss.

MotherNature CO2 Generator

A relatively new product to our CO2 enrichment range is the MotherNature CO2 Generator. This is an all-in-one kit designed to increase the CO2 concentration in your grow room. The larger capacity of this product means that it will effectively increase CO2 levels in areas up to 2.4m2, from 400ppm up to 1200ppm. It Increases the concentration of CO2 to greater than double the PPM of the normal atmosphere simply, effectively and economically. The generator is designed to be plugged into a lighting timer/relay to only pump CO2 when your plants need it, during 'lights on'. During the dark period, the active CO2-producing bacteria within the MotherNature unit come to life, re-energising the bucket.

Ecotechnics CO2

If you're looking to generate and regulate CO2 on a larger scale, Ecotechnics CO2 equipment can comprehensively provide this to your room. The complete kit comes with everything you need to effectively monitor and dose larger grow spaces. Simply refill your CO2 canister when you're low and the Ecotechnics system will take care of everything else.

 

Any other tips?

It’s best practice to situate your CO2 generator as high as possible, as CO2 is heavier than air and will fall. With that being said, ensuring that you have good air circulation in your room (which you should already have!) will mean that CO2 is continually mixed in with your air and will mitigate this effect.
While it is beneficial to establish a 'closed loop' environment that doesn't waste valuable CO2, it's important to purge your grow room of stale air by having your extraction fan come on for a few minutes at least once per day.
CO2 can be lethal in high concentrations, so it's important to take safety precautions and install additional monitors throughout the indoor space.