Using CO2 for growing cannabis to maximize your yield

Published Mar 11, 2019 11:00 a.m. ET

 In a developing world of cannabis and related products, it can be difficult to navigate the hundreds of different methods used to increase yields. Many don’t realize that some of the most effective ways to maximize the potential of any indoor grow rooms are relatively natural. Some of the most popular tips and tricks are focused on the most practical rules of nature. All plants require food, light, and micronutrients to thrive. Give a plant the very best of everything it desires, and you will have a successful crop.

Why use CO2 to grow cannabis?

All plants require at least some CO2 to survive. However, marijuana plants are slightly different as they need much more than the average house plant. Adding CO2 to a grow room can increase your overall yield by as much as 20% which is a huge driving factor behind choosing this method to grow weed.

How do CO2 systems for indoor growing work?

Cannabis plants breathe just like we do, only their primary source of nutrients is CO2. This is why they are considered such a positive addition to the environment when grown and used as a replacement for harmful plastics. CO2 is what turns the light you provide into energy for the plant through a process called photosynthesis. CO2 systems will allow for you to force more carbon dioxide into the plant’s environment which will give it more energy and nutrients to feed off.

Who should be adding CO2 to a grow room?

While adding CO2 to a grow room can certainly provide great benefits to some growers, the ones who will truly benefit will depend on the lighting that is used in their grow rooms.

Low powered light fixtures

Without the presence of CO2 your marijuana plants will die as they slowly suffocate from the oxygen-rich environment. Certain light fixtures such as fluorescent or CFL lights emit such weak amounts of light that the levels of CO2 found in the air will likely always be more than enough for your cannabis plants to process the light. For them, adding CO2 will be a waste of time, as the plants will only consume as much as they require for energy.


High powered light fixtures

High powered lights are what the CO2 method was invented for. High powered lights provide stronger much more nutrient dense rays of light that cannot be fully consumed by a marijuana plant without providing higher than average levels of CO2. Adding more CO2 means your crop will utilize the light in a more efficient way which in turn will provide additional photosynthesis. Since there is more energy available after adding CO2 to a grow room, there will be more rapid growth resulting in a more significant yield come harvest time.

How to use CO2 for growing weed

The first thing you will want to ensure before using anything is that your grow room is as sealed up as possible. As much as airflow is generally a good thing when using CO2 much of it will escape through walls windows and doors. Your second step should be to purchase a fan that can be placed on the ground. Thisis because CO2 is incredibly heavy and once the room is sealed you will need the air movement to keep it in contact with the leaves. When you use CO2 to benefit cannabis plants the ideal amount you will want to maintain is between 750-1500 ppm which can provide a 20%-30% increase in your yield. You do this in a couple of different ways.


Dosers are essentially CO2 injections for plants. A doser will come stored in a sealed tank of sorts that will come equipped with a pressure gauge, timer, meter, and a whole bunch of rubber tubing. They are incredibly easy to use. Just set up the timer, turn the dial to the amount of CO2 you want to maintain, and you’re good to go until it runs out. The timer should always be programmed to turn off when the lights are off as additional CO2 at that point in time is useless.


CO2 generators are one of the most effective CO2 systems for indoor growing, especially for those with larger than average grow rooms. They use natural gas and propane which once burned will produce carbon dioxide. One single Co2 generator with one burner should be sufficient enough coverage for an 800 square foot grow room. This option is a convenient method of CO2 injection for weed plants because it lasts much longer, covers more area, and it doesn’t have to be removed to be refilled as dosers do.



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