Using CO2 and What To Consider

By Stoney Tark 

What Are Stomata?

These are what the plants use to exchange CO2 from the atmosphere and produce oxygen as a by-product. Imagine small mouths that open and close according to the temperature and humidity of the growing environment. Stomata function best when the humidity levels are high, meaning that the dryer the conditions, the lower the amount of exchange is made. Once lights have come on inside the grow room, plants will take 60 minutes before their stomata are open and ready to perform.

Applying CO2 to the grow room before the first hour of lights on will be a waste as the plants have no way to utilize it. In order to push your CO2 levels to 1200-1500 ppm, temperatures do need to be within the range of 30-35 degrees Celsius. However, this range can be far too hot for indoor gardens and cause more harm than good, especially for the less experienced grower who has been convinced CO2 is the way to go.

How Is CO2 Measured?

When dealing with a gas, it is necessary to use an infrared sensor. Carbon dioxide, carbon monoxide, methane, and water vapor are detectable using infrared equipment. This is down to how the gas absorbs the infrared radiation that is done is an identifiable manner. The actual unit measurement is in parts per million (P.P.M) and is also the same measurement taken when using a T.D.S stick for nutrients. 350 - 450 ppm is the typical atmospheric concentration outdoors and, although most growers will recycle fresh air from outside into their tents or grow rooms, increasing the level of CO2 the plants can consistently absorb can increase yields significantly speeding up the process of photosynthesis.

Installing CO2 In The Grow Room

Before installing CO2 into the grow room using air tanks, there are a few things that you should consider. Carbon dioxide is a heavy gas, meaning that the streaming of gas needs to fall from the tops of the plants down. This can be done by using an air hose that is designed to disperse the gas through an even-sized number of holes into the air. Oscillating fans can aid in the distribution of CO2 around the canopy of leaves of the plants, however, plants can rapidly absorb any carbon dioxide so a consistent supply and high levels of 1200-1500 ppm must be met.

Increasing the level of CO2 the plants can consistently absorb can increase yields significantly speeding up the process of photosynthesis.

CO2 tanks are the go-to solution for large scale indoor grows that are running high-powered lighting to supplement CO2 and the integrity of photosynthesis. There are cheaper solutions to produce your own CO2 at home and they can involve using active yeast buckets, which do work yet require regular maintenance and also can create unwanted smells attracting pests. Digital controllers can be installed into the grow rooms which will allow you to manually control the levels of CO2 being output. Normally these will work alongside the temperature controllers which power the exhaust fans, wall fans, and humidifiers.

Things To Consider

The best way to think about using carbon dioxide as a supplement is to compare it to training your body at the gym. The mistake that many people can make is not finding the right balance between exercise, nutrition, rest, and recovery. The same principle applies when using grow lights, nutrients and using CO2.

As more growers are aware of vapor pressure deficit (V.P.D), taking into consideration the temperature and humidity and calculating the force that is present on the surface of the leaf tissue is something that can determine the uptake of CO2 your plants take. High V.P.D means that plants will grow in low humidity, and low V.P.D means your plants will have higher relative humidity, as a result performing the exchange of CO2 to oxygen much faster.

In the same way that the V.P.D chart is simply a guide for the grower to follow, considerations must be made to the exact amount of V.P.D, relative humidity, carbon dioxide and, of course, the timing of the plant's life cycle. The dangers of running a room that is excessively hot accompanied by high humidity levels can introduce a world of problems that could otherwise be diverted.

Pathogens and plant disease will thrive in conditions that are warm and humid and, whilst the risk of pathogens is reduced at a relative humidity of less than 40%, then finding the right balance between temperature and CO2 output can determine how susceptible you are to an airborne attack.

During the early seedling stage and until flowering occurs, plants should be grown in high humidity ranging from 70-75% with daytime temperatures of 24 degrees Celsius and a nighttime temperature of around 18-20 degrees Celsius. When flowering plants indoors, you will want the relative humidity to reduce to the 30% mark.

If using CO2, plants will benefit mostly during the growing phase of 18/6 as the humidity will be most high, the V.P.D will be low. Exceeding temperatures of 24 degrees Celsius can cause excessive transpiration from both leaf tissue and the roots, so be warned of the potential environmental risks of increased temperatures and increased levels of CO2.

How to use CO2 benefits

Plants adding CO2 to an indoor garden have many benefits. These include a much faster, vigorously growing plant that, as a result, will produce bigger yields than if not using CO2 as a supplement.

The rate of photosynthesis will be at a maximum, meaning plants will produce carbohydrates much more quickly in response.

Finding the ideal levels of CO2 to introduce to your gardens should always be based on strict calculation and also taking into consideration the risks of high humidity during the flowering phase and how low humidity can reduce the uptake of gas by the stomata. As far as expenses and maintenance are concerned, acquiring air tanks and having a constant supply is not overly expensive and will really add a whole new dimension to the way your plants perform.