symptoms of smoking moldy weed

Moldy Weed – Side Effects, Detection, Causes, Protection and Solutions

Nothing ruins dank weed quite like moldy weed that is “dank” in the wrong way. For growers and users alike, having a supply of moldy weed is tantamount to lighting a fistful of cash on fire.

Mold on weed is not only unpleasant to smoke at best and dangerous at worst, but it also can ruin an entire batch of otherwise perfectly good herb.

Below are some tips for avoiding moldy weed mishaps and for keeping both flower and bud perfectly dried without ruining the buzz.

What is Moldy Weed and How to Detect It

For those who know their cannabis strains – the appearance, the smell, the taste – detecting moldy weed is easy.

When smoked, something about the taste of the bud will be off, and if the bud is infected, then the mold might even be visible and/or give off a foul odor.

Marijuana growers should regularly check their plants for mold. Mold on living plants will either appear green and fuzzy or like a white powdery substance on the leaves and shoots. Plants also give off a natural reside, such as with pollen, and this residue can also attract the white powdery mold.

White powdery mold spreads easily, and airborne spores can quickly infect multiple plants, so if any signs of mold are discovered, the infected plant(s) should be removed from the grow tent or room.

When mold infects plants early in the grow process, the spread of the infection can be contained and treated with a fungicide, and the crop can be saved. But for plants that have a heavy amount of mold infestation, the whole plant must be thrown out.

Bud smokers can visibly detect mold on their weed using a 420 scope, a jeweler’s loop, or anything that magnifies the bud for higher visibility.

There are also stash jars with magnifying lids that make it easier to get an up-close look at the herb, whether to check for signs of mold or to admire the bud in general.

Mold on weed will stand out from the sticky hairs and the THC-laden trichomes that look like tiny crystals. The appearance of mold on dried bud can vary, from sticky webbing to white/gray/yellow fuzz, or black or brown spots or spores.

Moldy weed will smell of mildew, or it may give off a rancid odor, almost like urine. Another way to detect moldy weed, although this method is definitely not recommended, is by the flavor. Mold has a distinct, off-putting taste that is easily discernible to the experienced user.


Although it is not recommended, there are times when one can accidentally smoke some moldy weed.

Depending on the extent of the mold infection, the side effects of smoking moldy weed can range widely.


  • Severe coughing/ lung irritation (different from the usual coughing from smoking bud)
  • Tight chest / restricted breathing
  • Chest pains
  • Dizziness or queasiness
  • Headache
  • Bleeding nose
  • Fever

If you think you may have smoked moldy weed, it is best to contact a health care provider.

Although according to the DEA, there are no reported deaths due to marijuana overdose, if there is mold on the bud, smoking moldy weed can have some serious adverse effects.


Mold spores are actually in the air all around us, and when they find an area heavily laden with moisture and a lack of air circulation, they take root and grow.

Mold can spawn and spread in grow rooms with stagnant and humid air. It can also manifest on dry bud when the bud sits in a stash jar that has moisture in it, and that is left capped for enough time for the mold to grow.


There are many steps that growers must take throughout the entire grow process to prevent moldy weed. First and foremost, a grow room must have proper air circulation and controlled humidity levels.

Mold grows best in wet, humid environments with stagnant air, so it is important to make sure that humidity levels are maintained, both in humid and dry climates, and fans or ventilation systems should be in place to keep the air fresh while using full spectrum grow lights.

For more information on maintaining humidity levels in a grow room, check out this video.

The drying and curing process is also crucial for preventing mold. Once the flower has been harvested and the plant is ready to be dried and cured, the timing and the method of drying can affect the plant’s vulnerability to mold exposure.

If the drying process is too lengthy, then mold can develop. On the other hand, if the plant is dried too much, then the bud will be harsh to smoke. When drying weed, humidity levels in the room should be around 50% with room temperatures of around 70°F.

For the curing process, when curing in jars, the humidity levels should be around 60-65% with room temperatures around 70°F. Throughout the curing process, it is also important to open the curing containers regularly to allow air circulation.

Bud smokers can protect their herb from mold through proper storage. Using plastic bags to store weed is not recommended because they trap moisture.

There are plenty of different types of stash gear, like glass jars, mini tins and boxes, or beautifully carved wooden boxes, for storing weed in optimal environments. Hygrometers not only function as elegant stash boxes, but they also control humidity levels within the container.

What to do with moldy weed

Unfortunately, there is not much that can be done with moldy weed aside from throwing it out. Growers who detect moldy weed at an early enough stage can treat and eliminate mold with fungicides.

For users, moldy weed can be smoked with certain methods – such as with bongs, or cooking the weed at 200°F for ten minutes, or super critical extraction – but none of these fully eliminate mold.

On a positive note, in states where marijuana is legal for medical or recreational use, dispensaries put their products through rigorous testing and inspection processes, so the risk of moldy weed is low.

Moldy Weed – Side Effects, Detection, Causes, Protection and Solutions Nothing ruins dank weed quite like moldy weed that is “dank” in the wrong way. For growers and users alike, having a supply

Symptoms of smoking moldy weed

Mildew Kush doesn’t sound appealing, does it? It doesn’t, not just because it’s gross, but because it’s dangerous, too.

Unfortunately, legal markets have seen their fair share of moldy weed recalls over the past few months alone. In January, Michigan regulators recalled 48 pounds of medical marijuana due to mold.

A month prior to Michigan’s order, Colorado agencies recalled an entire batch of weed from one operator that affected at least 10 Denver-based dispensaries.

Also in December, Canada’s government weed supplier, the Ontario Cannabis Store, recalled 25,000 grams of pot after a customer found mold on her cannabis.

So the mold scare is real. Here’s how to ensure it never ends up in your pipe.

Related: What Moldy and Disgusting Weed Actually Looks Like


Eye-Ball It

The easiest and most cost-effective method for spotting mold on weed is the naked eye. Tokers will notice something that looks similar to cobwebs on or within the buds. Spider mites also leave behind actual webbing that can look identical to mildew, but you shouldn’t be smoking those, either.

Powdery mildew, a form of mold, can sometimes look like dusted kief to the untrained eye. However, closer inspection will reveal the powder isn’t kief at all, but something that resembles sawdust or the dust produced by kicking a puffball mushroom.

Other signs of mold or mildew include dark spots on otherwise green buds, yellow or gray fuzz, or the presence of slime. (Yuck.) Sometimes buds may also appear as if they were rolled in confectionery sugar, another sign of powdery mildew.

The Nose Knows: The Smell Test

Weed comes in a wide assortment of aromas, from hints of berries to that chronic funk that smells like you just ran over a wild skunk. But two scents can tip you off to moldy weed: the smell of human sweat or urine.

Of course, no one should ever smoke weed that smells like pee anyway, mildew or otherwise.

The smell test has limitations, though. Some noses are more sensitive to the nuances of weed fragrances than others. And tokers who are allergic to mold-derived antibiotics like penicillin may experience an allergic reaction.

Additionally, some molds and mildews don’t produce any smells, especially if the infestation only recently took hold.

Science, B! Use a Microscope

Obvious signs of mold, like seeing webby crud all over your buds, indicate the infestation was there for a while. Sometimes, however, newer cases of mildews and molds are invisible to the naked eye.

In this case, consumers can still detect if their weed contains mold. This method requires a microscope. In the age of Amazon, however, digital microscopes sell for less than $30.

Again, recognizing mold on weed by eye, even the aided eye, takes some experience. Mold and mildew produce little filaments called hyphae. Hyphae look nothing like the bud’s natural glandular trichomes, so if anything looks out of the ordinary, it might be mold.

Check the Media and Brand Websites for Recalls

Another safe practice for finding out if your cannabis contains mold is by checking local media for reports of recalls. State or city websites, as well as some company websites, may also post notices.

Although checking the news for moldy weed may seem dorky, it has worked in the past. In the case of the Canadian recall mentioned earlier, the woman who reported the mold only caught it because she’d read a news story on the topic. She said she never would have checked had she not known mold was even an issue with legal weed.

Why Mold Threatens Good Health

Why even care about mold on weed? After all, isn’t mold a source of medicine, just like cannabis?

Molds and mildew are fungi that thrive in moist environments with poor air circulation. With weed, the presence of molds or mildews indicates the plants are diseased, not extra medicated.

While some molds produce antibiotics like penicillin, treating an infection by smoking moldy weed is a really, really bad idea. Those allergic to penicillin could react violently to smoking mold, much less smelling it. Other patients, like those with compromised immune systems, may be unable to fight off the mildew’s spores, leading to moldy lungs on top of smoking shitty weed.

Furthermore, some molds and mildews produce toxins, called mycotoxins, that can’t be burned away. And even worse, making edibles with moldy weed will transfer those toxins wholesale into the food. (Double yuck.)

Basically, get your cannabis from trusted sources. Inspect every purchase before ever flicking a Bic. And always remember: webbing belongs in dark corners, not on weed.

Moldy cannabis has increasingly become a problem in legal markets. How can you tell if your weed has mold or mildew without forking over thousands of dollars to a lab?