CO2 for the indoor cultivation of marijuana plants

Reading Time 7 minutes
Image of the letters CO2 and a marijuana plant in the background
Image of the letters CO2 and a marijuana plant in the background


CO2 is good for plants, this is something that is generally known, but that does not mean that carbon dioxide must be supplied at all times and in any quantity. Plants absorb CO2 at certain times, but at other times they emit it and this is something that must be taken into account, because the lack of CO2 can represent a problem as well as applying it at certain times, and for this reason we have thought that it could It is good to have this article at hand, where we are going to make it clear how to use CO2 with cannabis plants grown indoors. Keep in mind that not everything is in carbon dioxide, it is important to have a powerful light so that the plants can assimilate it well, and if you are not sure which one may be ideal, I leave you here this other article in which we talk about The best lighting for indoor growing



⭐ CO2 and its relationship with plants



Plants need CO2 to carry out photosynthesis, combining it with light and water to convert it into carbohydrates and to be able to develop normally. During the day or the illuminated phase the plants consume carbon dioxide and emit oxygen, but during the night or the dark phase they do just the opposite, that is, they consume oxygen and emit CO2. As a general rule, in the air there is a CO2 concentration of about 350-380 PPM (parts per million) but cannabis plants are capable of assimilating much more, and that is something that can be very beneficial.

By increasing the concentration of CO2 in indoor cultivation, the photosynthetic activity also increases, and this is reflected in a higher yield of buds, faster flowering and maturation speed, and even in some cases an improvement in the final quality of the product. However, we must try to provide this element in its proper measure and only at times when the plants can truly take advantage of it to improve flower production.



⛳ How to use CO2 in indoor cultivation


In many cases, the contribution of CO2 for plants in vegetative growth is not good, since in this case, despite the fact that the plants grow faster, it usually results in spiky structures that are not good for indoor cultivation, since it is of interest that the plants have a more compact morphology so that the light is more effective. Some growers provide an extra carbon dioxide in vegetative to accelerate the growth of mother plants or save time in the making of the SCROG, but as a general rule it is not usually applied in vegetative growth.

The ideal is to provide CO2 during the flowering phase and only during the illuminated cycle, normally from the third week to a couple of weeks before harvesting, in this way the process of generating inflorescences that will end up forming the buds is greatly accelerated extent, achieving a performance improvement of 20% or 25% in many cases. It is also important to know that plants consume the CO2 available in the environment in approximately 30 minutes, they need time to assimilate everything, therefore with some CO2 generation methods it is not necessary to provide it at all times.

The way to use CO2 in indoor cultivation is from above, since this gas weighs more than oxygen and tends to fall downwards, and it is important to accompany the extra carbon dioxide with an increase in fertilizer doses, a An increase in temperature, and if possible a greater light output as well, is the best way for plants to take full advantage of the extra CO2.



Download completely free the marijuana dictionary
Free Download Cannabis Dictionary 2023 Edition
Insert a correct email address
You must accept the privacy policy
SITE OF SHOPS ONLINE S.R.L with CIF: B98262777 and address for notifications in C/ VEREDA MAS DE TOUS Nº 22 LOCAL C, 46185 LA POBLA DE VALLBONA, VALENCIA, Phone: 961658271 Email: customer(at)
At the name of Consulting we process the information you give us in order to provide the requested service, perform the billing of the same. The data provided will be kept as long as the business relationship is maintained or for the years necessary to comply with legal obligations. The data will not be transferred to third parties except in cases where there is a legal obligation. You have the right to obtain confirmation as to whether SITE OF SHOPS ONLINE S.R.L. is processing your personal data and therefore you have the right to access your personal data, rectify inaccurate data or request its removal when the data is no longer necessary

✨ Optimum CO2 level for plant bud growth


How much CO2 does a plant absorb? The improvement in performance can be clearly seen from 700 PPM, cannabis plants can assimilate up to 1500 PPM or even 2000 PPM, but that does not mean that it is good to provide so much, since the same thing that happens with the excess fertilizers and plants become stressed. It is also not advisable to start with the maximum contribution, the ideal is to start with little and gradually increase until reaching a maximum of approximately 1200 PPM, accompanying this increase with an increase in subscribers, light, temperature, etc.

Below you can see a diagram with the indicative data so that you can apply CO2 in your indoor cultivation in a similar way, but always keeping in mind that each variety may have different needs, and just as some can assimilate more nutrients than others. The same thing happens with carbon dioxide.


*(Indicative table for marijuana varieties with 9 weeks of flowering)*

3 800 1,4 26
4 900 1,6 27
5 1000 1,8 28
6 1100 2,0 29
7 1200 2,2 30



👌 Ways to make better use of CO2 in indoor cultivation


Before I told you that the plants need about half an hour to completely consume the available CO2, but in indoor cultivation we have constant ventilation that does not stop taking air in and out. So will the extraction remove the CO2 as well? That’s right, and a good way to not waste anything is to regulate the time that the extractor works, connecting it to a timer so that it activates only 15 minutes out of every hour. Surely now you are thinking, if I lower the extraction time, will the temperature inside not rise much? Well, you are right, but in this case it is not a problem because with the contribution of CO2 the plants can withstand a higher temperature without problems.

On the other hand, when the heat increases we force the plants to open the stomata of the leaves more to improve transpiration, and this facilitates a greater assimilation of CO2 by the plants at the same time that we save electricity and make much better use of the contribution of carbon dioxide.



📲 How to create CO2 for plants


There are different methods or systems to produce CO2, each with its advantages and disadvantages, from burners, pills, bags, etc. What is the best CO2 for plants? That depends on the type of grow and the conditions of the grower, professionals tend to use the most effective systems, but those can be quite expensive for people who grow for their own consumption. Here below you can see different methods to generate extra CO2 in your marijuana crop.



🚀 CO2 generator with propane gas burner


It is the most professional system, and there are several models available with a different number of burners. It is a rectangular device that contains 2 rings at the top so that you can hang it from the upper bars of the grow tent or fix it to the ceiling of the room. Although the initial investment is higher than what is necessary to buy other methods of CO2 generation, in the long run it can be cheaper because it works with propane cylinders.

Generador de CO2 con quemadores


✅ CO2 kit for indoor cannabis cultivation


The CO2 kit with a disposable bottle is from our point of view the most interesting in terms of quality/price. It consists of a 1 kilo CO2 bottle, an electrovalve and a reducer, and it is very comfortable and practical because you can only place the end of the tube where the CO2 comes out at the top of the crop, and the bottle with the rest of the kit can even stay out of cultivation. The solenoid valve can be connected to a timer so that it only provides carbon dioxide at the times we want.

Kit CO2 con bombona desechable
Buy CO2 Kit Disposable bottle



🔥 CO2 bag for small crops


It is the most economical method to increase the amount of CO2 available in the environment of indoor crops. The initial investment is minimal and does not consume electricity. It is a breathable bag that contains a mixture of up to 15 organic ingredients that cause a reaction that generates CO2. The only drawback is that you have to take it out of the grow at night, but with a single bag of CO2 Boost Buddy you have enough carbon dioxide to supply this gas to a 1.2 x 1.2 meter grow tent for approximately 6 months. After that time you can discard its content in the garden or the compost bin, since it can serve as fertilizer for the plants. It comes prepared to be hung at the top of the closet so that the force of gravity forces it to go down and that the leaves can assimilate it.

Co2 Boost Buddy
Buy Co2 Boost Buddy



🎯 CO2 Boost for passive generation in large crops


CO2 Boost is a cube that contains an organic mixture that releases large amounts of CO2 for 2 or 3 months, depending on its use. It comes with a dispenser that is placed on the lid of the bucket and contains a small compressor that extracts the gas and takes it to a hose that must be placed on top of the crop so that the CO2 falls to the plants. It is designed for large crops, of at least 6 square meters to make the most of it. It does not produce heat, and you can only purchase the bucket if you already have the dispenser.

CO2 Boost Cubo Con Dosificador De CO2
Buy CO2 Boost With Pump System


👾 TNB Naturals Enhancer CO2 Dispenser


Another great option to increase the amount of CO2 in your marijuana crop without having to invest a lot in materials. It is a bottle that contains a mixture of organic compounds, and its operation is as simple as adding hot water and shaking for the chemical reaction that releases CO2 to take place. It is recommended to shake every 2 days, and with a single TNB Naturals Enhancer dispenser you will be able to increase carbon dioxide up to 1200 PPM in a grow tent of 1.2 x 1.2 meters or less for a time that can oscillate between 15 days and a month, depending on use.

Dispensador de CO2 Enhancer TNB Naturals
Buy CO2 dispenser TNB Naturals



🎬 CO2 pills for marijuana plants


These pills are not to increase the environmental CO2, they are mixed with the irrigation water to improve carbonic fertilization, since in this case the carbon dioxide is absorbed by the roots of the plants. Each package comes with 60 tablets, and each tablet is enough to provide CO2 to 100 liters of water, so it is a very interesting investment, first because the improvement in the plants is more than remarkable, but also because you have enough to various crops.

Pastillas de CO2
Buy CO2-Tablets



🧐 Conclusion


Increasing the availability of CO2 to plants grown indoors can have many advantages, as a yield increase of 25% or even more can be achieved, but it has to be done well so as not to stress the plants and cause problems. Remember that CO2 is 100% effective in crops where all the parameters are correct, if you are not sure if you are doing it right I invite you to read this article where you will see excellent tips for growing cannabis indoors, and if you liked this information you will I would appreciate it if you share it on your social networks.



⚠️ Frequent questions


Where does CO2 enter plants?

Plants absorb atmospheric CO2 through their leaves, more specifically through microscopic holes that can open and close called stomata. On the other hand, they can also assimilate CO2 through the roots, in this case as carbonic fertilization, but in both cases it processes it to produce carbohydrates, among other things.


Can there be excess CO2 in plants?

There can be poisoning due to excess CO2, and this can cause stress in the plants. However, for an excess to occur, it would be necessary to exceed 3000 PPM for a very long time, something that is not easy. Something that does tend to happen when we give too much CO2 is that certain nutrient deficiencies may appear, especially magnesium, which is why it is recommended to gradually increase the dose of fertilizers as we increase the CO2 contribution.

Click to rate this post!
[Total: 4 Average: 2.3]
Did you like the article, share it on social networks!
Fran Quesada Moya
Fran Quesada Moya

See more posts
Participate in the discussion: 1

Leave a Comment

  1. Avatar for Suzanne wallace

    Finally folks won’t think I am crazy for moving my wine making fermitation jugs into my grow room!!!! I used to ‘Bulk Up’ my tomatoes this way before I got my Hemp grower license.

    I grow my own microbes too!

    Gypsy Rose Hemp Farm