Woman holding cannabis bud

Mold on Weed: Here’s What to Know

Originally published 4/12/22, expanded 4/6/23

Concerned you have mold on weed you've had in storage? It may be easy to determine if old bread or cheese is moldy. However, mold on weed isn’t always as easy to spot.

To make matters worse, smoking moldy weed could lead to an experience you don't want in terms of ill effects or simply an unpleasant taste. Here's a look at the dangers of mold on marijuana, how to spot weed molding, and how to prevent the problem in the first place.

Avoid Mold With Humidity-Controlled Stash Jars

The Dangers of Smoking Moldy Weed

Can you smoke moldy weed? You really shouldn't smoke weed that you know is moldy on purpose, but if it happens by accident, there are a few things to know.

If you accidentally smoke moldy weed once or twice, you’ll likely be fine - it’s typically more of an unpleasant experience than a dangerous one. Nevertheless, smoking mold is not a great idea because there is always a potential that you could experience ill effects due to the present mold spores. Smoking moldy weed can lead to:

  • Coughing
  • Vomiting
  • Nausea

    If you are allergic to mold (a relatively common allergy), smoking moldy weed can cause inflammation of your respiratory system, particularly your sinuses and lungs. This can result in asthma, congestion, and sinus pain.  

    Certain fungi can be especially dangerous. In a UC Davis Study, researchers examined fungus on weed samples purchased from legal cannabis dispensaries. They discovered Cryptococcus, Mucor, and Aspergillus – fungi linked to lung infections in people with weakened immune systems. Aspergillosis can be a major concern with mold on weed, as this type of mold can cause a severe lung infection that causes chest pain, bloody sputum, difficulty breathing, and fever.

    What does moldy weed look like?

    moldy cannabis flower

    For the most part, mold on weed will show up as a grayish or whitish, often webby coating (but the exact colors of the mold can vary). The mold will likely be coating outside areas of the bud, but it can also be deeper within the flowers.

    Trust your nose when looking for fungus on weed. Moldy weed usually takes on aromatics not common to the cannabis plant, smelling mildewy or even a little like old hay.

    Moldy Weed vs Trichomes

    Trichomes are shiny, sticky crystals that form on cannabis flower. Trichomes look almost like sparkling glitter. By contrast, mold will take on different appearances depending on the type. You may see spots that look powdery and white, gray and fluffy, or even black.

    What does mold on weed taste like?

    If you light up and your weed has an "off" taste, it is best to pay attention. Moldy weed can taste a lot like what you would expect: like you've inhaled a mouth full of mildew. You may still recognize the slight taste of terpenes depending on the extent of the mold, but those enjoyable flavors will definitely be overpowered by the dank taste of mold.

    How to Fix Moldy Bud

    Unfortunately, once you've got mold on weed, there's not a lot you can do. Some people will trim away what appears to be moldy and then smoke or vape what's left, but even this is questionable. Mold spores can be microscopic, and when you're dealing with tightly bundled clusters of flower, it can be really hard to tell where there is mold and where there is no mold. Therefore, when in doubt, throw it out just to be safe.

    How to Prevent Mold on Marijuana

    proper cannabis storage

    Proper storage is the key to keeping mold away from your weed. Mold spores are a natural part of the environment, but they gravitate to organic materials where certain environmental conditions are met, and the spores will be most likely capable of growing and thriving. To prevent mold on weed, you will need to control everything from temperature and light to oxygen exposure and humidity in the storage container. Here are a few tips to keep weed fresh and mold-free.

    Avoid hot or frigid temps

    Certain temperatures are more conducive to mold growth. The best temperature range for weed storage is above 50°F (10°C) and under 77°F (25°C). Therefore, storing your stash in the fridge or freezer is not a good idea. Likewise, you don't want to put your weed outdoors in the cold or heat for long periods.

    Watch the humidity levels

    To prevent mold from growing, the level of moisture in your cannabis has to be controlled. Shoot for humidity levels between 55 and 65 percent - above that range, conditions become more favorable for mold growth, while below that range, cannabis can become dry and crumbly. Maintain the appropriate level with a humidity control device.

    Use the right storage container

    When you intend to store weed long-term, make sure you are using a container built for the purpose. A glass jar is best, but look for a jar that has an airtight lid, something to keep out the light, and can accept some level of humidity control. For example, our Evergreen Storage Solution contains a glass jar with a silicone sleeve and a humidity control pod to prevent mold and keep your weed fresh.

    Well-Stored Weed Means Long-Term Quality

    Under the right storage conditions, weed can last a really long time without you having to worry about mold. Be sure to check out our full guide on storing cannabis.

    Evergreen Storage Solution

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