Spotting mold on bread or cheese is pretty easy, but on cannabis? Not so much.

Here’s everything you need to know about what to look for, whether it’s safe to smoke moldy cannabis, and how to keep your stash mold-free going forward.

What to look for

Moldy cannabis usually has a grayish-white coating. If you’re not a seasoned consumer or grower, though, it can be easy to mistake trichomes for mold and vice versa.

Trichomes are those sticky, shiny crystals on the leaves and buds that give cannabis its aroma.

Unlike trichomes, which look like little hairs that almost appear to glitter, mold has a gray or white powdery appearance.

Mold also has a distinct odor to it, so your nose may notice the mold before your eyes do. Moldy weed usually has a musty or mildewy smell, or it may smell kind of like hay.

Is it safe to smoke it?

It probably won’t kill you, but it’s still not recommended.

In healthy people, smoking moldy weed isn’t likely to have a detrimental impact on your health — barring the general risks of smoking, of course.

If you smoke moldy weed, you might experience symptoms like coughing, nausea, and vomiting, which are more unpleasant than dangerous.

But if you’re allergic to mold, you could end up with inflammation of your sinuses or lungs and symptoms like:

• sinus pain
• drainage
• congestion
• wheezing

In people with weakened immune systems or lung conditions, inhaling smoke from weed that contains certain mold species can have serious health consequences.

Fungi like Aspergillus, Mucor, and Cryptococcus can cause serious and even deadly infections in the lungs, central nervous system (CNS), and the brain in people with compromised immune systems.

A UC Davis study found these and other types of potentially harmful fungi on cannabis samples bought from dispensaries and growers in Northern California.

Is there any way to remove the mold?

Not really.

You may be tempted to cut off the obviously moldy bits and smoke the rest, but it’s not a good idea. Life’s too short for bad bud.

If you can see mold or mildew, you’re better off tossing it. It’s not going to taste or smell good anyway, and could make you feel sick.

How to protect against mold

Storage is everything when it comes to preventing mold.

Exposing cannabis to the wrong temperature, light, humidity, and oxygen can promote the growth of mold.

Here’s what you need to keep in mind.

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.