How to Prevent and Treat Cannabis Mould Infestations

While you’ll hear and see insects and rodents crawling around, they aren’t the only living things that like to snack on weed plants. As it turns out, mould, a much smaller, elusive enemy, also likes the taste of cannabis. Let’s go over how you can protect your crops against the most common species of mould, preventing and treating it in turn.

Whether you’re growing cannabis or any other crop, mould poses a big threat to both indoor and outdoor growing operations. This initially invisible enemy can quickly gain a foothold in your garden, reduce yields, and even ruin flowers post-harvest. As we go along, we’ll cover exactly what mould is, introduce you to the most common species, show how to prevent it, and cover how to treat your plants if you detect it.

You’re out on the other side of town running some errands and realize that you might as well pick up some more weed while you’re at it. You pull into the parking lot, readjust your mask and enter the nearest dispensary prepared to follow whatever rules they have posted to keep everyone safe. From the moment you enter, you don’t get a great feeling from this pot shop. The display cases are sparse, the floor is dirty, and you’re greeted with indifferent stares from the staff. You already miss your local budtender. However, you’re already here, the prices are similar, and they’ve got your favorite strains listed on their menu. You pick out your strains, pay up at the counter, and walk out the door rubbing the sanitizer into your hands.

Once you get home, you pull out your weed and see…something. You can’t quite place what’s wrong with it, but this weed looks a little off. The bud has some fuzzy spots and discolorations where it should be deep green. Is this mold? Is it a dense patch of trichomes?

If you’re unsure how to spot moldy weed, you’re not alone. Plenty of consumers have run into the same issues when purchasing weed from less than reputable dispensaries. Or sometimes from honest shops purchasing from less-than-reputable growers. However, if you’re not sure how to tell whether or not your weed has gone bad, don’t worry. PotGuide is here to guide you on the easiest ways to recognize moldy weed.

What Mold Grows on Cannabis?

Cannabis, like any other plant, can become a host for organisms like mold or mildew if they’re grown in the conditions that these fungi like best. Humid or moist environments are where cannabis molds like Botrytis, Aspergillus, Cladosporium, Rhizopus, Mucor, and Penicillium thrive.

If your weed is moldy, it means that it was grown in a place without proper air ventilation or humidity control. Or it could also mean that the producer didn’t dry and cure it correctly after harvesting.

Is Mold on Cannabis Bad For You?

Mold is not good for you to inhale, and definitely not good for you to smoke. There are many different kinds of cannabis molds out there, but any one of them can be extremely dangerous. While mold on cannabis probably won’t kill anyone with a healthy immune system, it can lead to coughing, nausea, vomiting, headaches, and other serious conditions like aspergilloma. Even more, if you have allergies to mold, you could end up with inflamed sinuses, congestion, wheezing, or a sore throat from bad weed.

Things get much more dangerous if your immune system is compromised or your lungs are damaged, as smoking moldy weed can cause a bunch of serious health issues.

Once inhaled, the mold can take up residence in your lungs and start growing. This can cause serious lung infections that may require hospitalization. Worse, once it enters into your bloodstream it can spread throughout your central nervous system. This is, of course, a worst-case scenario, but still should be avoided if at all possible. Serious home growers have to be very wary of mold for this reason. Many of them are growing either to treat themselves or someone else with a medical issue that could compromise their immune system.

Isn’t All Cannabis Tested For Mold?

While growing weed yourself could put you at risk of having mold on your plants due to an amateur set up, isn’t the weed you bought at the store lab tested for mold, pesticides, and other contaminants? After all, that’s part of the information you’ll find on any cannabis label. First off, it should be said that most growers are honest and work incredibly hard to create a safe, healthy product. If they find mold on their harvest, they’ll take the loss and destroy all the contaminated product before getting the lab involved.

However, some less-than-scrupulous growers will instead pick the best buds out of that batch and send those non-contaminated samples over to the lab. The employees at the lab will have no idea they’re being tricked since the lab is not on-site at the grow. They also don’t have the budget to send anyone out to get their own samples at the grow to test. The sample bud will register as passing the test, the lab will give the ok, and then the grower can start selling to unsuspecting or similarly dicey dispensaries.

What Is Mould?

The world “mould” probably conjures up bleak images of rot and decay if your mind’s eye. While mould doesn’t look pretty when it devours cannabis plants, it plays one of the most fundamental roles in nature.

A type of fungus, “mould” encompasses a large group of taxonomically diverse species. Much like other fungi, they branch out while forming a multicellular network of small filaments (hyphae), forming a dense mass of fibres known as mycelium.

Moulds don’t possess a digestive system. Instead, they pump out enzymes that break down substances like plant matter and wood on the outside of their bodies. With these traits, they play the role of nature’s great decomposers. They break down waste, plant matter, and dead animals into smaller particles, returning them to the soil to continue the circle of life.

Where Mould Comes From

Moulds belong to the fungal kingdom, which emerged as a specialised branch of this family tree around 1.5 billion years ago. The 100,000 different species that have appeared since have adapted to their own unique surroundings.

For the most part, though, mould loves moisture, and it’ll go wherever it can find the most optimal conditions. That also applies to many plants, but, unlike plants, moulds don’t conduct photosynthesis. Instead, they require organic matter—which includes cannabis flowers—as an external food supply. Many of them also favour stagnant air, hence the proliferation of moulds in places like bathrooms and kitchen cupboards.

Spores and Reproduction

Moulds reproduce by sending out plumes of spores into the air. They can be likened to the seeds of a plant, although they behave in a very different manner. See, instead of sending out actual seeds, they wait for the moment they land in a prime environment. If that moment ever comes, they send forth hyphae into the world in search of food.

Some spores are asexual and successfully mate with themselves, giving rise to the next generation. Other spores create hyphae that require a mating partner. Hyphal cells from two different spores find each other and mate, and their nuclei merge, creating a zygote capable of further reproduction.