What Does Weed Mold Look Like?
Learn | 09.26.2023

Moldy Weed: What You Need To Know

Do you know how to tell if your herb is moldy? Here are the basics of what to look out for and the harsh side effects of smoking moldy buds.

Smoking moldy weed can have some seriously unpleasant side effects.

Whether they appear as plain old allergies or a serious infection, you want to steer clear of moldy weed at all costs.

But how do you know if your bud has gone bunk? What does weed mold look like? Depending on whether or not you’re growing or simply consuming harvested flower, molds and mildews can take various forms.

Here are the basics of what to look for when identifying if your weed has gone moldy.

What Does Weed Mold Look Like?

There are several ways to tell if your cannabis is a little “off.”

When cannabis has been taken over by mold, it’s pretty easy to spot. Just like bread or cheese, gray or white fuzz are two of the most common culprits that will devastate your stash.

However, mildew can also look like a dusty white powder on fan leaves or parts of the bud. This white powder is aptly called powdery mildew.

If you find moldy buds, don’t consume it. Dispose of it in an area where it will not contaminate other plants, and make sure the mold has not spread to other buds.

Some things to look for in dried flower include:

  • Dampness
  • Musty, sweet, and stale odor
  • Grey or white fuzz
  • Specks of white powder, like white dust
  • Allergic reactions, pain, and heavy coughing after consumption

What Does Weed Mold Look Like When Growing?

What does weed mold look like while growing?

Preventing mold starts in the grow room or greenhouse.

In order to keep the area clean and free of diseased plants, growers must:

  • Maintain appropriate temperatures
  • Carefully control humidity
  • Reduce contamination risks

Recognizing the early stages of molds and mildews can save your entire crop and ensure it’s safe to ingest for the consumer.

Here are some basic things to look for while you’re growing:

  • White powder developing on leaves
  • Fuzzy white or gray hairs on buds
  • Yellowing, dying, drooping leaves (could be a sign of root rot)
  • White or gray fuzz in the soil
  • Musty, stinky roots
  • Discolored or dying roots
  • Musty smelling buds

The Different Kinds Of Molds In Cannabis Plants

There are many different molds and mildews that can affect the cannabis plant.

Many molds vary by region, so there are many possibilities for plant and human infection. For the most part, the best protection against mold while growing is to keep plants in a clean, dry, and well-ventilated area with moving air.

Here are three common cannabis pathogens and how they might affect you:


Aspergillus is a fungus that produces mycotoxins, including some that are thought to be carcinogenic.

This mold can cause lung infections, which can be quite serious for those with compromised immune systems. Back in 2011, there were two case studies of medical cannabis consumers who developed a condition called chronic pulmonary aspergillosis (CPA) after suspected exposure to cannabis that was infected with Aspergillus.

The condition caused symptoms of emphysema and improved after patients were treated for Aspergillus infection and refrained from cannabis consumption.


Cladosporium is a common plant fungus that often grows on porous materials like wood and paper.

It causes symptoms of hay fever and can trigger asthma attacks, though this type of mold does not produce mycotoxins.

With chronic exposure, inhaling Cladosporium increases your chances of developing pneumonia.


Botrytis is the fancy name for gray mold, and it’s one of the most common cannabis pathogens.

This fungus can cause an allergic reaction and acute respiratory problems when inhaled.

These problems may be worse in those with:

  • Weakened immune systems
  • Prone to autoimmune diseases
  • Generally sensitive to environmental allergens

Can Smoking Moldy Weed Make You Sick?

The short answer is yes.

There are a few reasons why smoking moldy weed can cause adverse health effects for just about anyone.

Mold spores can survive in surprisingly harsh environmental conditions, including being burned, only to take up residence inside the warm and damp environment of the human body.

If your immune system isn’t up for the match, this can cause lung infection. Moldy weed can also make you sick thanks to compounds called mycotoxins and endotoxins.

Mycotoxins are compounds that sit on the outside of mold spores and in small fragments of mold. They’re referred to as toxins because they are harmful to the human body and can trigger irritation and illness. This is especially true if you’re exposed to them consistently and in large amounts.

Coupled with these mycotoxins are compounds known as endotoxins. Endotoxins are molecules released by bacteria as they die. Typically, molds and endotoxins go hand-in-hand, making exposure extremely agitating.

Endotoxins, by themselves, are known to worsen symptoms of asthma and contribute to lung irritation. Inhaling a batch of mycotoxins and endotoxins together can cause inflammation.

Chronic exposure to pro-inflammatory molds and mildews can aggravate autoimmune conditions and increase your chances of developing an infection.

In the worst-case scenario, this infection can contribute to pneumonia and possibly spread to other parts of the body. Signs of acute mold and mildew exposure include:

  • Headache
  • Fatigue
  • Weakness
  • Light sensitivity
  • Brain fog/memory difficulties
  • Cough
  • Asthma or allergy attack
  • Chest pain
  • Dizziness
  • Changes in mood

How To Reduce The Risk Of Smoking Moldy Weed

It’s important to note that small traces of molds and mildews can be present on your cannabis even if it is not visible.

For some, this trace amount of mold exposure is enough to cause illness or allergy. The best way to reduce your risk of inhaling mold is to purchase laboratory-tested cannabis from a regulated access point.

Often illicitly produced, cannabis buds grown without proper care and regulations can contain:

  • Residual pesticides
  • Fertilizers
  • Fungicides
  • Pathogens

Here’s how to reduce your risk of smoking moldy cannabis:

  • Pick buds that smell delicious to you and that don’t have musty undertones
  • Don’t pick buds that feel damp or have a wet, grassy scent
  • Don’t consume cannabis that you know has been out in the rain or has gotten wet
  • If growing, put up a greenhouse before the weather gets bad and make sure it’s humidity controlled
  • Properly store your cannabis in air-tight containers in a dark, dry area
  • Keep growing rooms clean
  • Use a humidity pack while storing your bud
  • Give your bud a once-over before consuming
  • Pick laboratory-tested cannabis whenever possible

Unfortunately, global legal restrictions on the cannabis industry mean that millions of people lack access to quality-tested recreational and medical cannabis.

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