How To Prevent Mold In Cannabis Grow Rooms

Mold is a significant problem for many cannabis cultivators. It can quickly cause problems in how your plants grow, how much yield you get from them, and how much money it costs to keep the mold under control. This blog post will discuss how to prevent mold in cannabis grow room with some tips that commercial cultivators have proved!

What is mold in cannabis?

Mold is a type of fungus that can grow on any organic substance- including cannabis. It grows in multicellular filaments, and they are several different types of fungi species. It generally appears fuzzy as a black, green, or white powder and can cause significant problems for your plants if it is not under control.


Common types of mold in cannabis are:

  • Bud Rot – This affects the buds, aka Botrytis
  • Root Rot – This affects the roots, aka Fusarium Oxysporum
  • Powdery Mildew – This affects the leaves aka Golovinomyces Orontii

The number one way to prevent mold in your cannabis grow room is to have a proper air circulation system. Proper air circulation means that the air should be constantly moving and not stagnant. Fans are a great way to achieve this, and you should have fans blowing in all directions (including up). In addition, make sure that your exhaust fan is powerful enough to expel all of the hot air from your grow room. Finally, if you have an HVAC system in your grow room, make sure it is properly sealed and insulated.

Another way to prevent mold in your cannabis grow room is to keep the humidity levels under control. The ideal humidity level for cannabis cultivation is between 40-50%. You can achieve this by using a dehumidifier or running an air conditioner. When taking clones and transferring plants, be sure to do it quickly so that humidity does not get out of control in your grow room!

One last tip for how to prevent mold in your cannabis grow room is something called “air pruning.” Air pruning means that you will be removing the bottom leaves of your plants so that the air can circulate better. In addition, it helps increase yields because the plant is not wasting energy on growing leaves that will be removed!


Identifying Molds In Cannabis

Botrytis Cinerea / Bud Rot

Commercial cannabis growers are likely to encounter Botrytis, a common fungus that can cause extensive damage to crops. The symptoms of Botrytis infection in cannabis plants are:

  • Gray, fuzzy mold growing on stems or flowers.
  • Brown lesions on the stem, which can lead to plant death.
  • Buds that are covered in a grayish fuzz and have a wet appearance.

If you see any of these symptoms, it is essential to take action immediately. The fungus can spread quickly and cause significant damage to your yields and plants.



Aspergillus is another common fungus for commercial cultivators that encounter within cannabis grow rooms and in buds. The symptoms of aspergillus infection in cannabis plants are:

  • Brown, circular lesions on the leaves.
  • Dark brown spots form around more prominent veins of the leaf.
  • White, cottony growth on the underside of leaves.

If you see any of these symptoms, it is vital to take action immediately. Aspergillus can spread quickly and cause significant damage to your yields and plants.


Powdery Mildew / PM

Powdery mildew is one of the most common problems commercial cultivators deal with when growing cannabis. The symptoms of powdery mildew infection are:

  • White powdery substance on leaves and buds, looking like a layer of talcum powder.

If you see any of these symptoms, it is essential to take action immediately. Powdery mildew can spread quickly and cause significant damage to your yields and plants.

I hope these tips have been helpful for how to prevent mold in your cannabis grow room. Remember, prevention is always easier than trying to fix a problem already there!


Preventing Mold In Cannabis Is The Key

When growing indoor cannabis, it is essential to avoid any mold spores in the air that can contaminate the plants, spread the mold throughout your plants, and damage them. A great way to prevent this from happening is getting an Air and Surface Purification system to prevent mold and any cross-contamination.


Provide Clean Air and Sanitize Surfaces

AirROS is a commercial air and surface purification system that can prevent pathogens, mold, viruses, yeast, and bacteria, reduce cross-contamination, and eliminate cannabis odor. AirROS purifiers utilize and create ROS (Reactive Oxygen Species). First, it kills pathogens and odor as it passes through the air purifier. Then, it sanitizes the air that comes out of the purifier, enters the environment, and continues to sanitize all surfaces it contacts. Here is the 2 stage process:


Phase 1- Primary Air Cleaning

Placed within your room’s airflow, air from the environment containing microorganisms enters the purifier’s internal chamber. The reaction chamber creates non-thermal plasma and generates ROS. ROS has comprised of 5 short-lived, highly Reactive Oxygen Species:

  • Atomic oxygen,
  • Singlet oxygen,
  • Hydroxyl radical,
  • Superoxide and
  • Peroxynitrite


These break down carbon-to-carbon bonds that sanitize the air and destroy all bacteria, molds, viruses, and other pathogens as they pass through the reaction chamber.


Phase 2- Secondary Surface & Air Cleaning

Provides Surface sanitation and continued Air sanitation. The purified air now diffused into the environment contains longer lived Reactive Oxygen Species:

  • Gas-phased H2O2- hydrogen peroxide
  • Low concentration levels of O3-ozone

That further sanitizes room air and surfaces. So again, in addition to treating the ambient air as it passes through the reaction chamber, using the H2O2 and O3 diffused into the environment, our units will further sanitize all Surfaces and control Odor, resulting in clean air and surfaces 24/7.

Mold is a common problem in cannabis grow rooms, especially for commercial cultivators. It is crucial to have the proper airflow and ventilation when growing cannabis indoors to ensure that mold does not take root. Including an air and surface purifier will help prevent mold from settling on surfaces within the room. If you are experiencing problems with recurring mold growth in your indoor marijuana cultivation operation, contact us by submitting a form! We can provide specialized solutions specifically for your needs or schedule a call with one of our specialists.

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