While moldy weed is a rare exception and not the rule, there are exceptional occasions where mold spores can spread either during the cultivation process or sneak in past quality control checks. Moldy weed is not life-threatening but could cause respiratory problems, nausea and be detrimental to overall health.

How to Spot Moldy Weed

High-quality cannabis will be sticky from the abundance of trichomes on the bud’s surface, smell fresh, and will have yield slightly when squished between one’s fingers.

Legal cannabis purchased from dispensaries undergo a stringent quality assurance process, so while the final product shouldn’t contain any mold, it’s always helpful to remain vigilant.

Spotting moldy weed is easy, and once you’re familiar with the signs, you can do a quick spot test yourself before consumption.

For starters, moldy weed will be wet instead of dry and sticky like it usually is. This wetness signals that mold has already penetrated the core of the cannabis bud, and it’s a sign that consumers should throw it away.

Secondly, be sure to visually inspect the bud in your hands to see if there are fuzzy spots or patches on the surface. These fuzzy areas can range in colour from white, brown, black or gray and additional mold signs.

Giving your buds a squish test before they’re consumed is a great way to check for mold.

Fresh cannabis is springy yet firm and will stick to your hands slightly. Moldy weed will be limp and wet and covered in patches of coloured fuzz. Taking the bud in your hands to do a squish test helps you do all of these tests at once and is one of the best ways to ensure your cannabis buds are safe for consumption.

What Causes Mold to grow in Cannabis?

Mold spores are everywhere, so the chances of it propagating are high.

That being said, Health Canada’s legislation on cannabis has set a legal limit for the amount of moisture that can be present. This moisture limit is lower than what is accepted in the unregulated market, thus lowering the chances of mold growing after being packaged and sealed.

Since mold spores are everywhere, the biggest cause of mold growth is extra moisture. When improperly packaged or sealed, moisture can penetrate the packaging and cause mold to grow before the consumer purchases it.

However, mold growth can also happen during the cultivation, harvesting and curing process. If cannabis is processed in a hot, humid, or poorly ventilated environment, mold can easily take hold and begin to propagate.

Overcrowded growing environments present the perfect conditions for mold to grow as the mixture of cannabis plants, heat, and poor airflow combine to spread mildew.

Poor plant genetics can also play a role. If a phenotype or strain of cannabis has a weak plant immune system, they can be less hardy and more vulnerable to suffering from Botrytis cinerea or ‘bud rot.’ Unlike mildew, bud rot starts from within the bud and is difficult to spot until it makes its way outside the bud.

This kind of mold can ruin an entire harvest, so cultivators must do their best to maintain optimal growing conditions in addition to securing the best plant genetics.

Know Your Mold

Moldy weed is something you want to be discerning with; however, its chances of appearing in your final product are low. Cannabis consumers should always do a quick squish and visual check on their buds before they’re consumed to ensure that they’re of the utmost quality.

For cultivators, the measures undertaken are stringent and varied. You’re likely to find mold in your bread before you find mold in your buds! That being said, being vigilant and careful in your own private consumption causes no harm and could make you appreciate the care and effort undertaken by growers!