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28 January 2021

How CO₂ Increases Yield in Indoor Cannabis Grow Environments

The ultimate goal in growing cannabis is to procure high-quality, deliciously scented, trichome rich buds that produce the highest yield possible. While this is the fundamental objective in cultivating the intoxicating plant, many marijuana growers struggle to succeed. What if growers could incorporate a valuable resource into their grow environment to maximize yield?

Introducing Carbon Dioxide (CO2) into a grow room allows a cannabis plant to absorb more of the colourless gas, consequently increasing photosynthesis. As a plant creates more energy through the light-related process, it utilizes the influx to develop healthy plant growth. Adding carbon dioxide to a grow environment increases photosynthesis, ultimately enriching the outcome of the plant.

Vibrant, happy plants produce more luscious buds. For most growers, maximizing yield is one of the finest achievements in growing cannabis. Incorporating CO2 into a growing space boosts overall plant vitality resulting in bountiful harvests. Many seasoned marijuana growers tout yield expansion of 20% – 30% when CO2 is added to their grow set-up.

How Does CO₂ Effect Cannabis Plant Growth?

Carbon Dioxide is a colourless gas that is naturally present in the atmosphere. Cannabis plants absorb CO2 through tiny openings on the underside of their leaves called stomata. These tiny pores regulate the flow of CO2, oxygen, and water. As CO2 is absorbed into the plant, the gas is directed to chloroplasts, the plant organelles that contain light-absorbing chlorophyll where photosynthesis occurs.

Photosynthesis, an intricate sequence of reactions, takes light energy from the sun to convert CO2 into chemical energy stored in sugars to feed the plant. With the help of water uptake through the root system, this fascinating process ultimately releases the byproduct oxygen back into the atmosphere. Excess water from the cannabis plant is also released back into the atmosphere through transpiration.

Outdoor marijuana plants have the benefit of utilizing as much CO2 as they need to maximize growth. Abundant high-intensity rays from the sun promote photosynthesis, stimulating cell production in plants. Outdoor plants naturally produce strong roots, thick stems, and leaves as they adapt to the environment.

Indoor growers can capture similar effects by introducing CO2 in their cannabis grow setting. Creating an optimal environment utilizing light, airflow, humidity, and temperature while adding proper CO2 levels promotes faster growth of cannabis plants. Knowing when, how to apply it, and how much carbon dioxide to administer in a grow room is key to increase yields.

Cannabis plant flowering after CO2 boosts plant growth

Optimal Indoor Environmental Controls for Introducing CO₂

Photosynthesis can only occur when there is high-intensity light, such as that directed from the sun. Indoor grow set-ups must mimic those levels of light energy for a cannabis plant to synthesize CO2. CFL’s and T-5’s will produce enough light for a plant to photosynthesize, although CO2 conversion is relatively low.

Metal Halide (MH), High-Pressure Sodium (HPS), and LED lights, on the other hand, provide ample wattage to elevate energy exchange. The amount of CO2 administered in a grow room is directly proportional to the amount of light emitted from light sources. Furthermore, factoring in the room size determines how much light and CO2 are necessary for peak synthesizing.

Marijuana plants flourish in a grow room with ideal temperatures and relative humidity in the air. When administering CO2 into the environment, increasing temperature and humidity levels stimulate plants to process photosynthesis abundantly. Cannabis can tolerate higher temperatures between 29⁰C – 35⁰C and humidity levels between 60% – 70% when CO2 is injected into the cannabis grow chamber. 

However, keep a watchful eye out for heat stress on your plants with these elevated inputs.

Carbon dioxide naturally regulates in normal atmospheric conditions. Keeping the precious gas contained requires a closed, airtight growing space. Applying CO2 to a chamber to increase photosynthesis is senseless and costly if the gas escapes before the cannabis plant can absorb it. Sealed grow rooms provide a secure setting allowing marijuana plants to capitalize on energy transfer. 

Additionally, cannabis plants grown in an enclosed area must have fans to provide sufficient air exchange. Bright lights, high temps, and humidity can create an overwhelmingly stressful environment for plants without proper airflow. Circulating air also helps move carbon dioxide and oxygen throughout the grow room, optimizing the climate for excellent growing conditions. 

When to Activate Carbon Dioxide in a Grow Room

Marijuana plants in the vegetative stage typically grow best when lights are on an 18 – 6 hour light cycle. Because plants photosynthesize dependent upon light energy, CO2 applied during light hours promotes peak growth, especially in veg. As plants rest in darkness, they are no longer producing energy but instead using up stored reserves. Cut the CO2 when the lights go off.

When cannabis plants transform into the flowering stage, energy transfer in the plant begins to change. Instead of directing the flow to grow stalks, stems, and leaves, the focus realigns to flower production. The sugars utilized by the plant during the flowering phase direct energy to create big, bountiful buds.

Many commercial cannabis operations will continue supplying CO2 throughout the flowering phase to increase bud development. Other experienced growers will discontinue the process two weeks before harvest, allowing the plant to use up all stored reserves.

How to Introduce CO₂ to a Cultivation Environment

There are several methods for applying CO2 to your cannabis grow room. For small enclosures, simply opening the door or tent flap each day will supply a rush of fresh air to your marijuana plants. Large cannabis operations, on the other hand, require more sophisticated devices.

CO2 generators and compressed CO2 tanks are unique systems that regulate the amount of gas injected into a grow environment. Generators burn propane or natural gases to create carbon dioxide through combustion. While these machines are very proficient, they increase heat and humidity substantially.

Similarly, tanks holding compressed CO2 are safe and extremely efficient. These components do not produce heat and control carbon dioxide levels with regulators. The limiting factor to this design is continually filling or exchanging tanks.

The schematics of both of these systems control injection rates into the grow room automatically. Adjusting parts per million (ppm) readings of carbon dioxide-based on light intensity output is easily achieved with both of these methods. While these systems make it easy to control CO2 levels, the cost of an apparatus required to maintain a grow space can be costly.

There are other natural methods of creating CO2 that can benefit plant growth, utilizing some of nature’s creativity. Fermentation and composting rely on microbial activity to change organic molecular structure while releasing CO2 during decomposition. Unfortunately, these methods expunge minimal amounts of carbon dioxide unless there is abundant gas exchange available.

Dry ice, the solid form of carbon dioxide, is another alternative for obtaining the gas. This enrichment process can be used in small enclosures or for short-term use, but regulating CO2 levels using chunks of melting dry ice can be challenging.

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How Much CO₂ is Required in a Grow Room for Maximum Yield?

Carbon Dioxide levels in the atmosphere are measured in parts per million (ppm). Outdoor readings have increased over the years and recently measure around 400 ppm. Indoor marijuana growers have the advantage of manipulating CO2 levels in determining optimum measurements for specific environments.

Available CO2 in an indoor environment must match light intensity. For instance, light emitted from a low wattage bulb may evoke photosynthesis but at a much slower rate. Ppm readings below 200 may keep the plant alive, but growth is slow.

As readings increase to 400 ppm, though, photosynthesis begins to get busy. Adding more CO2 to a grow room increases the energy exchange promoting luscious growth on cannabis plants. Photosynthesis really shines when light intensity is between 4500 – 5500 lumen/m², and carbon dioxide measurements are 1200 – 1300 ppm. These levels are a good range for many cannabis cultivation set-ups.

On another note, as many cannabis growers have come before us, they have determined and shared the absolute sweet spot for maximization of light to CO2 ratios. They have revealed light intensity of 7500 lumen/m² coupled with carbon dioxide readings near 1500 ppm is photosynthesis at its finest. Expect to have a bountiful crop under these ideal conditions.

Preparing for CO2 Infusions

Experimenting with CO2 in a grow environment is a challenging feat. It is hard enough at times to overcome hurdles from simply growing the plant. Dialling in optimal controls such as nutrient recipes, pest management, and environmental factors is best accomplished before introducing new procedures.

Be aware that carbon dioxide is a colourless gas that is safe for humans to breathe at low levels. However, elevated readings nearing 3000 ppm can be detrimental for humans, and breathing CO2 at 5000 ppm is fatal. Always read safety precautions on any equipment used to disperse the gas. Most importantly, monitor the grow room by taking daily ppm measurements to ensure safety.

In general, cannabis seeds from stable genetics raise the bar on successfully growing marijuana. Knowing a plant’s growth characteristics and positive attributes greatly enhances the chance of an abundant crop. Before delving into infusing your grow room using CO2, be sure to choose high-quality, genetically proven cannabis seeds.

Here at Marijuana Grow Shop, we offer top-shelf feminized, regular, and autoflowering cannabis seeds brought to you from extinguished breeders from all over the world. Our genetically established line-up of popular cannabis strains such as Gorilla Glue #4 and Sour Diesel is sure to elevate your success when incorporating CO₂ into your grow room. Visit marijuanagrow.shop to discover the unlimited possibilities of genetically stable seeds to maximize yield when injecting carbon dioxide into your next cannabis crop.     

Post author
Charle Thibodeau
Charle’ Thibodeau is a freelance writer with almost a decade´s experience, specializing in cannabis content for the past two years. A strong motivation to educate, inform, and promote the culture surrounding this miraculous plant is her earnest mission.
See more from Charle Thibodeau

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