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Is it OK to smoke moldy weed?

Is it OK to smoke moldy weed?

You may be a fun guy, but that doesn’t mean that you want any fungi on your weed. We apologize for that pun, but moldy weed is no laughing matter, and can not only ruin your cannabis but also cause some health complications. 

Why does weed get moldy?

Fungi and mold are everywhere around us and play a very important job at breaking down and decaying organic matter. Their spores float through the air and land on all sorts of things, including your bud. Whenever these spores land, if conditions are right for growth, then mold can appear.

When trying to protect your cannabis (or your house) from mold, there are three main factors to keep an eye on:

  • Humidity: Mold and many other fungi thrive in moist, humid environments, which is why it’s so commonly found in the corners of showers or underneath a leaky sink.
  • Heat: Mold thrives especially well in the warmer months of the year, when the air is more humid.
  • A lack of ventilation: Mold does better in areas where there is not adequate airflow, which can be a real problem for indoor cannabis growers, especially if they have a high density grow. 

During cultivation, cannabis plants can get moldy if they are grown somewhere warm and humid that does not have proper air circulation. After harvest, cannabis can get moldy if it is stored improperly with the same conditions – humidity, heat, a lack of airflow – all of which can also happen at home with your personal stash if it isn’t stored appropriately. 

The same factors can also affect cannabis after it’s harvested, dried and cured, including at your home with your personal stash. You can help prevent mold on your cannabis by making sure to store it correctly.

cannabis mold mold can appear similar to glimmering trichomes
To the untrained eye, some mold can appear similar to glimmering trichomes.

How to prevent moldy weed:

  • Keep your cannabis stored in a cool, dry place where it is not exposed to sunlight or any other heat source.
  • Keep your cannabis in an airtight container.
  • Do not store cannabis in the freezer or refrigerator. The changes in temperature when opening and closing the door can cause condensation that can lead to the development of fungus.

How to prevent mold when growing weed:

  • Make sure to have adequate airflow in your indoor grow area, including ample use of fans and exhaust vents to clear out the stale air.
  • Don’t pack the plants too densely in the grow area and be sure to remove any dead material from the plants as it occurs.
  • Keep a tidy workspace and be clean. Mold spores can easily hitch a ride on a grower and end up on the buds, setting the stage for problems later.
  • Be sure to dry and cure your cannabis properly.
  • When curing, make sure to also “burp” the container every day or two in order to get fresh air inside. 
  • Keep a watchful eye on the temperature and humidity of your grow room.

What does moldy weed look like? 

The best way to know if your plants have mold is to get to know the most common types of mold that affect cannabis. 1

  • White, powdery mildew: This commonly occurs on the leaves of the cannabis plant. It may resemble trichome crystals to the naked eye, but it has more of a white color when observed under a microscope.
  • Botrytis (“bud rot” or grey mold): Typically grey or brown in color, it can work its way through the colas of the plants causing them to droop, eventually rendering the plant useless. 
  • Web-like fungi: This is a general term for many types of fungi. It is usually brown, white or grey, and resembles fuzz or cobwebs. Note that spider mites, a common cannabis pest, can also create webs that resemble fungus and the two problems are often confused by amatuer growers.

You can spot these same tell-tale signs in your personal stash, as well as some other red flags: 

  • Wet, squishy buds that aren’t dry and sticky
  • A musty, stale, or sweaty smell 
  • An overly harsh taste and smoke
moldy marijuana bud rot
Bud rot is typically grey or brown in color, it can work its way through the colas of the plants causing them to droop, eventually rendering the plant useless

What happens if you smoke moldy weed?

Sure, you can smoke moldy weed, but you’ll probably regret it. 

For most people, smoking moldy weed will result in at most an irritated throat and some coughing. But people who are allergic to mold can have a much more severe reaction and could need medical treatment. 

Moldy cannabis poses the greatest risk to those with compromised immune systems, who could develop serious infections and potentially require hospitalization. 2

The bottom line? Avoid smoking moldy weed and make sure to only purchase your cannabis from reputable producers.  

Is it worth saving?

If you spot a little bit of mold on a single solitary bud in an entire sack of top shelf herb it’s completely understandable that you wouldn’t want to part with the entire stash. And while it’s certainly possible that the mold did not make its way to any other parts of the rest of the flower, you’re better off erring on the side of caution. After all, we’re talking about microscopic fungi and it’s highly likely that there is at least the beginnings of a mold outbreak on your herb even if it’s invisible to the naked eye. 

When in doubt, toss it out. There will always be more weed. 


  1. Punja, Z. K., Collyer, D., Scott, C., Lung, S., Holmes, J., & Sutton, D. (2019). Pathogens and Molds Affecting Production and Quality of Cannabis sativa L. Frontiers in plant science, 10, 1120. https://doi.org/10.3389/fpls.2019.01120
  2. Gargani Y, Bishop P, Denning DW. Too many mouldy joints – marijuana and chronic pulmonary aspergillosis. Mediterr J Hematol Infect Dis. 2011;3(1):e2011005. doi:10.4084/MJHID.2011.005
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