What to Know About Moldy Weed

by Haley Mills · February 1, 2023

Moldy weed may not seem like a big deal, but it can actually be pretty dangerous. Here’s what you need to know about mold and your weed.

moldy weed

Since medical marijuana legalization has gained popularity over the past few years, there have been a few cannabis plant recalls in recent years in states like Colorado, California, Michigan, and Florida due to potential health hazards from consuming moldy cannabis flowers.

Cannabis plants can start to grow mold in the growing, drying, or curing stages. Marijuana becomes highly susceptible to decay when the environment is unstable, so it’s critical to maintain properly controlled humidity and air ventilation.

Excess moisture is dangerous when it comes to the risk of weed mold. As a medicinal cannabis consumer, it’s essential to be aware of the potential issues and be able to identify and prevent moldy weed.

The Basics of Cannabis Mold

Mold is unsuitable for anyone’s immune system, but it may worsen in some individuals. Approximately one-fourth of the human population carries a particular gene that makes them more susceptible to developing mold-related illnesses.

Others who may be at increased risk for a harmful reaction if they use moldy weed include those with asthma, respiratory conditions, autoimmune disorders, chemical sensitivities, and other chronic medical conditions.

Different Types of Weed Mold

The seven types of mold that grow on cannabis plants are:

  1. Aspergillus
  2. Botrytis (Grey Mold)
  3. Mucor 
  4. Cladosporium
  5. Rhizopus
  6. Penicillium
  7. Powdery Mold

Is marijuana mold common?

Bud rot and mold are relatively common, especially with beginner growers and home cultivators, due to insufficient ventilation and an excess of moisture. Mold is a fungus that thrives in moist, humid environments with little adequate air ventilation. It reproduces through microscopic airborne spores.

Humans typically inhale or ingest tiny amounts of mold spores daily, which are not harmful to a healthy immune system. Once cannabis contains mold spores, it is challenging to get rid of them. They can survive combustion when heated and even the decarb process in an oven, but you will lose THC and only be able to make edibles or tinctures with the buds.  It’s best to discard the cannabis rather than smoke moldy weed.

Tips for Identifying Moldy Cannabis

Here are some tips for identifying the top six types of cannabis fungal infection to avoid the health consequences of consuming moldy marijuana.

Bud Rot

Bud rot typically begins with fluffy white growth in the middle or on the sides of the flowers. Botrytis can be seen with the naked eye as the color changes and becomes a dry texture. 

Powdery Mildew

In the earlier stages of powdery mildew, you can see small circles of white mold on the tops of stems and leaves. The fungi will become denser as it progresses, covering the buds in thick white powder.


Dark spots will quickly turn the lower leaves a yellowish-brown color. Visual signs to look out for are leaves that have wilted but not entirely fallen off and limp stems.


Common mold is found both indoors and outside. Generally dark green-black, Aspergillus spores create a lung infection after inhaling and can be found in the soil or cannabis buds.


Penicillium mold is predominantly found indoors. Its spores are typically light blueish-green and can ruin crops and harm humans and animals that have been inhaling mold. 


It produces a grayish-white coating on its spores and may infect humans with certain health conditions, such as when a person has a compromised immune system.

Potential Risks

While smoking moldy weed may not kill you, it is still not recommended and could have potential adverse effects, especially for those with certain chronic conditions.

If you consume moldy weed and are allergic, you could potentially experience the following mild effects: 

  • coughing
  • nausea and vomiting

You could also end up with inflammation of your sinuses and lungs, with more severe symptoms like:

  • sinus pain
  • drainage
  • congestion
  • wheezing
  • chest pain

Inhaling certain mold species can have severe health consequences for those with weakened immune systems or lung conditions. Some molds like Aspergillus, Mucor, and Cryptococcus can cause severe infections in the lungs, central nervous system, and brain for people with a medical condition related to the immune system.

Avoiding Moldy Cannabis

  1. Buds should be appropriately stored in a cool, dry place but try not to refrigerate or freeze them. The ideal temperature is just under 77°F.
  2. Remember to keep your weed in airtight containers, preferably with darker-colored glass. Weed does have an expiration date of approximately six months to one year.
  3. The ideal humidity level in your storage containers should be between 59% to 63%. You can purchase disposable humidity packs at many dispensaries that can be placed inside your mason jar. 
  4. Less airflow can lead to mold, so ensure proper ventilation in the storage room.
  5. Moldy weed will have a distinct odor. Cannabis products infected by mold will usually smell musty after closer examination. Exposing cannabis to a black light is an excellent way to see if there’s mold present so you can avoid moldy weed.

Can I Test my Cannabis for Mold?

Yes. Two standard scientific technologies are used to test and identify mold on cannabis plants. 

Plating-based technology measures the number of growing mold organisms in a sample.

Scientists can also utilize DNA-based or polymerase chain reaction-based technology to identify the presence of mold from a sample.

Can I Reverse the Mold?

You can’t do much to reverse the presence of mold or bud rot. You may be able to save other parts of the plant if you notice it early; however, that would require carefully removing the moldy parts and hoping the rest of your cannabis plant can bounce back.

Therefore, the only natural way to fix moldy marijuana is to prevent mold growth altogether, which would require adequate storage in an airtight container, fresh air ventilation, and a controlled temperature.

Leafy DOC can Help!

Leafy DOC offers a straightforward process, knowledgeable customer support, and an excellent experience.

The price is competitive without sacrificing quality, and they offer health services from a health coach even after you’ve obtained a medical card. With over 20,000 patients and hundreds of consumer reviews, this is the website for obtaining a medical card fast and securely.

 Here’s how it works:

  1. Book appointment. Skip unnecessary trips to the doctor’s office and make your appointment from the comfort of your home. Provide basic medical history and book your appointment.
  2. Match with a physician. Connect with the right doctor for you and easily talk to your provider on your phone or tablet. The provider will evaluate your condition and will address your questions.
  3. Receive your medical card. You’ll receive a Physician’s certification, and the Leafy DOC team will be available to address any questions you may have and support your upgraded lifestyle. If you are not approved for the card, there is a money-back guarantee.

Leafy DOC’s healthcare consultants can answer any questions about cannabis products and the potential benefits and risks associated. In many locations, you can see a doctor online and obtain a medical cannabis card from your home when convenient. This step will help ensure your medical marijuana is regulated and that you can keep your cannabis mold-free.

A medical marijuana card also provides the extra step of knowing where the cannabis product is from and what the strain is. This knowledge will benefit those looking to try new strains for medical conditions and will also provide an idea of which buds may be best for your local environment. 

Last Updated: January 30, 2024

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