CO2: essential for marijuana growing

We are going to talk about CO2 which is sometimes used in the cultivation of marijuana in order to explain the reaction of plants when using this gas. It is a pretty straightforward post so that all of you can understand what the use of CO2 when growing marijuana indoors is. We will post a more detailed and technical article about this in the future.

First, we need to talk about chemistry to become familiar with this gas.

What is CO2?

CO2 comprises 1 carbon atom and 2 oxygen atoms. It is a linear chemical molecule and its formula, which was developed by Lewis, is: O = C = OCO2 comprises 1 carbon atom and 2 oxygen atoms. It is a linear chemical molecule and its formula, which was developed by Lewis, is: O = C = O

CO2 is also known as carbon dioxide. Under normal temperature and pressure conditions, CO2 is a colourless, odourless, non-flammable, inert gas commonly known as carbonic gas. Is in part the product of aerobic fermentation or combustion of organic compounds and the breathing of living plants (marijuana plants, trees...) which actually use and need more CO2 than they produce themselves during their night period. Therefore, marijuana plants also produce CO2.

Carbon dioxide in the air is measured in ppm or parts per million and is usually always present in our cities with a ratio of about 300 ppm (0.03%).

CO2 is not a toxic gas for humans in small amounts but can be deadly from 100.000 ppm, i.e. 10% of CO2 in the air breathed. Do not worry: the amount of CO2 that is needed to improve a crop of marijuana will be around 1.500 ppm (0.15%) but one must always be careful, and this is why we recommend using reliable CO2 systems.

CO2 is often confused with carbon monoxide (CO), which is a highly toxic gas.

Effects of CO2 on cannabis:

Like all plants, cannabis absorbs atmospheric CO2 through their stomata and, with the help of chlorophyll, uses the energy generated by a light source to combine carbon dioxide and water in order to produce the necessary sugar for the plant development . This process is known as photosynthesis. CO2 absorption allows marijuana plants to perform better and to speed up their metabolism, so you will be able to harvest between 5-10 days earlier by using this gas.

Some varieties of marijuana such as Naranchup, Black Bomb, Heaven’s Fruit or Guayita react better at it and their performance will increase significantly, although all Philosopher Seeds’ seeds available in its catalogue will like some CO2.

For growing marijuana, we recommend 1.500 ppm if you want to increase yield, although each grower can use their own parameters.

When is best to use CO2 for growing marijuana indoors?

Philosopher Seeds recommends applying CO2 only if all other cultivation parameters are totally under control, i.e. climate, sufficient light output, irrigation and nutrients... Otherwise, it would be a waste of energy and money. We can say that applying CO2 in marijuana cultivation is intended for growers with a very wide experience.

CO2 is given to the crop when cannabis plants start the flowering cycle.

Applying CO2 to a cultivation room during the growth phase is not recommended because the plants would develop too fast and their height would go out of control and would make things more complicated...

During the cleaning period of plants, 10 or 15 days before harvest, it is not recommended to provide CO2 either, so the gas supply is cut from that moment.

CO2 is only supplied when the lights are on, never at night. Hence most CO2 control probes have a photo cell which can identify whether it is day or night.

In short, the plants need to absorb more CO2 than they it is the air during the day but they produce it at night (in smaller doses).

Marijuana plants need more heat than usual to be able to absorb CO2 so increasing the temperature between 28°C and 32°C in during the day is recommended, which makes its use ideal for summer crops.

To avoid waste, the growing space should be as airtight as possible.

How to provide CO2 to an indoor cannabis crop?

There are several ways of providing CO2 and, in any case, at Philosopher Seeds we recommend the use of gas bottles or a CO2 generator

Whether you are using gas bottles or generators, the safest is to use a digital controller to apply CO2, as it allows you to be aware of the amount of gas in ppm in the air at any time. In this way, you know at a glance if all goes well.

These devices are usually quite expensive but you’d better off investing in something safe and reliable from the start. These systems control ventilation so they stop the extractors when CO2 is being applied. Some of them also control moisture and other parameters.

Examples of CO 2 digital controllers: Ecotechnics controller o Superpro hydroponics.

If you have a low budget and can’t afford this kind of equipment, you can still go for less automated controllers, which are equally effective when well mastered. You will need more time to set them up and find out how to combine air extraction with the application of gas so they are not done at the same time. If you opt for these systems, Philosopher Seeds recommends investing in a simple digital CO2 meter on its own.

CO2 is a heavier gas than air so it is applied above the plants so that it falls on them. Applying carbon dioxide causes a rise in moisture so you should note that using a dehumidifier might be necessary to avoid the appearance of mould.

It is essential that the growing space is properly aired using fans that move the air and make it circulate in every way.

Plants with CO2 will have a greater need for nutrients, so EC (electro-conductivity) of the nutrient solution will be higher.

We hope this post helped you to gain a deeper understanding of the use of CO2 on crops.

Thanks for reading !