As you probably know, healthy plants require the right amount of nutrients to thrive, but another important component they also need is carbon dioxide, also known as CO2 to be able to grow.
You may have heard some growers using additional CO2 in their grow space and getting amazing yields from their harvest! Growers have actually been able to increase their yields by 30% by increasing their CO2 levels to 1,500 PPM from the atmospheric outdoor average of 400 PPM.
Are you considering adding additional CO2 to your grow area? If so, you have come to the right place to learn why additional CO2 is beneficial in your grow space.
Let’s first discuss what carbon dioxide actually is, how plants use it and how and when additional CO2 is beneficial in your grow area.
What Is Carbon Dioxide (CO2)?
Carbon dioxide is a colourless, odorless, slightly acidic gas composed of one carbon atom covalently attached to two oxygen atoms by double bonds.
Carbon dioxide occurs naturally in Earth’s atmosphere and is an important reason why plant life is essential to Earth's ecosystem, but you might be asking yourself why?
As you know humans breathe in oxygen through respiration and release carbon dioxide from the same process. However, plants work the opposite way. They breathe in carbon dioxide from the surroundings and release oxygen in a process called photosynthesis.
Without plants uptaking CO2 and undergoing photosynthesis the CO2 levels in the Earth’s atmosphere would reach suffocating levels in a short period of time.
How Is Carbon Dioxide (CO2) Measured?
CO2 levels are measured in PPM (parts per million) and typical levels in Earth’s atmosphere are around 400 ppm. This means that our air is composed of about 0.04% CO2, however in order to see benefits by using additional CO2 around your cannabis plant, the air within your grow space should have CO2 levels around 0.15% or 1,500 PPM.
How Do Plants Use CO2?
Just like humans sometimes need an extra supply of oxygen (O2) to help them breathe, adding additional carbon dioxide (CO2) to your grow space essentially does the same thing for your plants, it helps them breathe and grow!
Plants extract CO2 from their surroundings through their stomata, a small pore that allows the plant to “breathe” through. Plants have thousands of stomata in replace of lungs and are tiny openings in the plant cells that allow for gas exchange.
Plants produce sugar and oxygen from the photosynthesis process. The glucose or sugar is used by the plant to help grow, whereas the oxygen is released into the atmosphere.
Plants use a pigment called chlorophyll in their chloroplast to capture the sun's energy in order to undergo photosynthesis. Chlorophyll is a green pigment within the plant's leaves, and this is why most plants are green!
Interestingly, plants take in CO2 during the day but at night they give out small amounts through respiration. However, plants always are absorbing more CO2 than they are emitting.
Why Is Additional CO2 Beneficial for Plants?
When there is an abundance of CO2, plants are actually able to undergo photosynthesis at a faster rate than normal. Faster photosynthesis means faster growth, and overall it means larger yields.
A study was done using several different species of plants, and the growth of the plants at elevated CO2 concentrations of 475–600 PPM increased leaf photosynthetic rates by an average of 40%.
This increased growth is also reflected in the harvestable yield of crops, with wheat, rice and soybean all showing increases in yield of 12–14% under elevated CO2 in FACE (Free-Air Carbon dioxide Enrichment) experiments. Who doesn't want bigger yields?
How to Set up Additional CO2 in your Grow Space?
Interestingly, carbon dioxide (CO2) is heavier than oxygen (O2), because of this it’s important to place your CO2 above your cannabis plants or any plant to allow the CO2 to “rain” on the plant as it will force its way below oxygen in the air (O2).
You can also set up a fan to help keep the CO2 moving around the plant instead of sinking to the ground.
What is the Ideal PPM for Cannabis Plants?
As mentioned earlier, atmospheric CO2 levels are around 400 PPM, however cannabis thrives with a much higher PPM than that.
Additional CO2 is most effective for cannabis plants growth and increased yield if the CO2 levels are around 1,200 - 2,000 PPM.
On the other hand plants need a minimum of 150 PPM of CO2 to survive.
When Should You Use Additional CO2 In Your Grow Cycle?
If you decide to use extra CO2 for larger yields, it’s important to know when to provide the CO2 to the plants during their growth cycle. If the CO2 is used incorrectly, your plant can start to develop yellow edges or you can end up with a stretched out plant containing only a few buds.
Vegetative Stage and CO2 Use
If you’re looking for ways to increase the rate at which your plants grow, adding additional CO2 during the vegetative stage will allow this to happen much faster.
Flowering Stage and CO2 Use
In order to enhance growth and bud production significantly it’s recommended to add CO2 to your grow room for the first 2-3 weeks of flowering.
After the first three weeks, some growers believe that the additional use of CO2 is less effective, but others recommend keeping additional CO2 in your grow space until two weeks before harvest.
Using additional CO2 during the flowering stage not only speeds up the process but also enhances flower size.
Extra CO2 is especially important during the flowering stage for cannabis plants, however, it’s just as important to combine this additional CO2 with the right amount of lighting. Additional CO2 and twelve hours or more of light will allow the buds on your cannabis plant to get much thicker and thus provide a larger yield!
Do You Need to Use CO2 Overnight?
As plants close their stomata overnight, there is little to no photosynthesis occurring as the plant is unable to take in sunlight or energy. Thus, adding extra CO2 during this time doesn't help the plant grow as they are unable to take in the extra CO2. However, this also won’t harm your plant.
Other Benefits of Additional CO2 In Your Grow Space
Another benefit to additional CO2 in your grow space is the ability to keep your grow room or grow space at a higher temperature. Many growers consistently struggle to keep the temperatures down in order to prevent stress to your plants.
Having CO2 levels around 1,000 - 1,200 ppm allows your plants to grow at a higher temperature without causing any harm to your plants, and in this case you will significantly increase your plants growth.
How to Add Additional CO2 to Your Grow Area
There are a variety of different ways to introduce extra CO2 in your grow area, with pros and cons to each method.
Some methods include CO2 tanks, CO2 generators or CO2 enhancers. However, our favourite are CO2 enhancer bottles! These enhancers are easy to use, set up and maintain. Not to mention they are made from 100% organic ingredients and a lot safer than the other methods.
As mentioned before, it’s important to be aware that high concentrations of CO2 can be harmful to humans and animals and must not be inhaled as it could cause respiratory and health issues. CO2 levels that are 3,000 PPM and higher are harmful and can be lethal.
Importance of Lighting When Using Additional CO2
The intensity of your lighting plays a key role when it comes to adding additional CO2 to your grow area. Interestingly, if you were to just add extra CO2 into your grow room with low light conditions, the plant actually is unable to take in the extra CO2 until the light intensity increases.
High intensity lights are needed when you are wanting to add CO2 to your grow. This is because in an indoor grow space the lights provide the energy for photosynthesis, whereas the sun would provide energy for outdoor plants. As the light intensity increases there is more available energy for your plant and thus your plant is able to take in more CO2 if it’s supplied, which increases photosynthesis and in the end increases your plants yields!
If you enjoyed learning about how additional CO2 in your grow space with the use of lights can increase your yields significantly, check out other ways to increase your yields! We also have plenty of other growing blogs, if you are looking to learn more about growing at home.
Have you ever used CO2 in your grow space? Comment your experiences below!