Indoor CO2 Safety for Growers

Carbon dioxide enrichment is one of the critical components for indoor cannabis growers. CO2 - along with water and light - are necessary components of photosynthesis, the biological reaction that results in plant growth.

However, what indoor growers may not realize is that high levels of CO2 can also be dangerous. A sealed, closed indoor grow room can trap lethal levels of CO2 that can lead to severe negative health effects, such as dizziness, vomiting, and even death.

CO2 Generators in Greenhouses

For decades greenhouses have used CO2 generators that burn fossil fuels to generate carbon dioxide. Recent trends in enrichment have moved growers away from generators and into CO2 enrichment for two reasons: burning fossil fuels (typically butane or propane) is an incomplete process leaving residues on the plants, and, the low cost and neutral effects of CO2 make the gas cost-effective and easy to control.

CO2 Enrichment Today 

Indoor cannabis growers have solved the problem of burners by switching to compressed cylinders or bulk tanks of liquid CO2. A CO2 level controller maintains the required carbon dioxide levels for the grower - usually between 800-1,500 ppm. When CO2 levels drop below a specified level, a tank regulator with a solenoid valve is opened and releases CO2 to enrich the grow space. When the controller senses that the ppm level is at or above the prescribed high set point the controller triggers the valve to closes shutting off the supply of CO2.  This process is repeated continuously as the plants absorb the CO2 and deplete the levels inside the room.  Because the CO2 level is precisely measured and maintained, a well-designed system can save hundreds or even thousands of dollars in gas costs.

Our customers report a 30-40% reduction in gas usage when they move to a liquid CO2-based system. 

Utilizing Carbon Dioxide in Grow Rooms

The introduction of CO2 must be done in a precise, controlled, calculated, and well-planned manner. Simply opening a valve on a CO2 tank at one end of the room and hoping that the gas will evenly disperse is a terrible plan.

If you are getting into indoor growing, you should find an experienced HVAC contractor with experience in commercial growing to design a system for you. Simply installing fans or air standard commercial HVAC systems will not result in the desired effects.  HVAC contractors with experience in this market can help design a system that will regulate temperatures (it gets hot with all those lights on), find the correct balance for fresh vs. returned air, and ensure that the CO2 is evenly dispersed in the space removing hot and cold spots inside. Finding an experienced HVAC contractor will reduce the ramp-up time for that service provider to design and implement the necessary systems.  While any HVAC contractor wanting to get into the commercial growing space will need some time to educate themselves their industry experience with precise air exchange rates can help create a safe and effective system. Installing a system with correct CFM air flows, pressures, valves, and safety devices is critical to success.

Another source for the proper design, construction, and operation of a successful CO2 enrichment system is your local, independent CO2 supplier and draft beer technicians.  Their experience with CO2 systems for soda and beer is nearly identical to the systems used for CO2 enrichment in grow spaces.  Contact your local, independent CO2 provider, and ask what their experience is installing commercial grow facilities.  And as always, you can contact CO2Meter for help finding a reputable partner in your area.

As Dave, a grower in Denver told us, “Having the correct CO2 system is as important to me as the lights and even the plants. I might as well throw money down the drain without the right CO2 system.”

In addition, it is as important to also recognize during what times to supplement with carbon dioxide. Photosynthesis normally occurs only during daylight, and CO2 addition is never recommended nor required during the night hours.  Some controllers are designed with integrated light sensors so that the CO2 enrichment only occurs if the lights are on.

Sealed Grow Rooms and CO2 Safety

Unlike greenhouses used for flowers and vegetable growing, cannabis growers are moving to sealed grow rooms. The advantages are:

  1. Individualized plant strains
  2. Better control of temperature, water, nutrients
  3. Tighter control of plant diseases, molds, pests
  4. Regulate precise CO2 levels
  5. Minimize liquid CO2 costs
  6. Create a secure environment for growing

The downside of a sealed and secure grow room is that it creates a potential safety hazard for workers. A leak in the CO2 enrichment system is no different than a leak in any bar or restaurant keg cooler that uses liquid CO2 to carbonate beverages. Unfortunately, there have been far too many incidents in keg coolers and growers must realize the same potential hazards exist in these sealed spaces.

Because CO2 is heavier than air or oxygen it will “pool” at the floor first, then rise up until it fills a room. This drives down the oxygen level in an enclosed space to levels that can cause a person to pass out or even die due to the heavy percentage of CO2 that is being utilized. Humans can be asphyxiated in these situations or even contact CO2 poisoning if the CO2 levels are excessively high.  As 100% CO2 is being used, even a small leak in a supply hose or a faulty regulator can cause CO2 levels to quickly rise to the point that the air in the room becomes deadly. The increased use of pressurized liquid CO2 has resulted in several near-death experiences. As a result, local fire marshals and inspectors have begun to require the monitoring of CO2 for safety in legal cannabis growing operations. 

For example, in states like Michigan and California, local Fire Marshals and Inspectors now require licensed cannabis operations to install CO2 monitors for safety in each grow room. The device is meant to be set at levels that will ensure that asphyxiation does not occur. Other localities have begun requiring the addition of strobe lights, exhaust fan activation, and even having safety monitors make automatic supervisory notifications to the local fire department. 

In almost every state and municipality there are new laws regulating the use of stored CO2. However, even if you are growing recreational marijuana, if you grow and use compressed CO2 in an enclosed space (like a basement) it makes sense to invest in a CO2 safety monitor.

Grow Room CO2 Safety Monitor

For cannabis growers who use liquid CO2 enrichment, we recommend our Remote CO2 Storage Safety 3 Alarm.

  • Wired CO2 Monitor & Remote Display
  • Designed to Meet All Local Fire Codes
  • Meets NFPA, IFC, and NBIC Requirements
  • Meets OSHA and NIOSH TWA Standard

It meets all local codes, installs in minutes, and provides protection for you and any staff around stored CO2. Learn more about the grow room CO2 safety monitor.

Wireless CO2 Sensor for Monitoring Only

GrowFlux Wireless and Cloud Connected CO2 Sensor for growers

In addition, CO2Meter is proud to offer the GrowFlux CO2 Microclimate Sensor for CO2 monitoring only. This device is not intended for CO2 safety monitoring or control. 

The GrowFlux Microclimate CO2 Sensor can remotely monitor microclimates and CO2 levels, making critical measurements available from anywhere on your smartphone or PC. With the wireless and battery-powered design, the sensor can be placed anywhere among the crop, allowing growers to pinpoint CO2 enrichment dead zones and stratification.

Please note: With the first time purchase of the GrowFlux CO2 Microclimate Sensor, you must additionally purchase the GFX-AP Connection Access Point to securely connect to the cloud.

The Wireless and Cloud Connected CO2 Sensor features:

  • Wireless & Cloud Connected for Micro Climate Monitoring 
  • Accurate and Precise CO2 Monitoring for plant enrichment
  • Saves up to 10% on cooling energy consumption
  • Provides up to 500 feet of range indoors
  • Splash Resistant Design for Commercial Greenhouses/Indoor Farms

Carbon Dioxide (CO2) has remained a trending solution for many farmers, growers, and storage facilities worldwide for supporting growth and productivity in plant life, while also saving energy consumption. 

For more information on Carbon Dioxide (CO2) Solutions in Agriculture Applications, Speak to an Expert Today - 

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