Moldy weed is every cultivator’s nightmare. Here are the top reasons behind moldy cannabis and some helpful solutions.

moldy cannabis

Cannabis can play host to a slew of nasty organisms, just like every other living thing on our planet. Don’t let your carefully cultivated plants fall victim to mold. Below you’ll find a few simple measures you can take to prevent and manage parasitic fungus (mold).

Know your molds.

Molds are microscopic fungi present in virtually every environment. And they’re essential. Molds break waste and plant matter (fallen leaves and dead trees, for example) into small particles before returning them to the soil to naturally fertilize the earth. 

But for people, molds can be problematic. Molds often cause allergic reactions, and in rare cases, death. Mold is also a scourge for cannabis growers (and consumers – no one wants to consume moldy cannabis). There are two types of mold commonly found on cannabis:

  • White Powdery Mildew

    This is a grayish-white coating often mistaken for the sticky, sugary, glittery hairs of trichomes.

You can use your nose to determine whether it’s white powdery mildew or trichomes covering your plants. Here’s how. Powdery mildew smells as foul as it sounds, like the pungent musty, mildewy scent of a damp basement. Sometimes it can even smell like hay or urine.

  • Botrytis

    Botrytis (aka grey mold or bud rot) is harder to detect, but it’s not impossible to find. Botrytis shows up as lifeless brown patches in the leaves.

This lurking mold spreads fast, often infecting a living plant through a wound or opening, causing rapid cellular death. And once this mycelium has germinated, it’s often too late to save the plant.

The devastation these molds can unleash on your grow room is horrifying, and the fact that they can launch spores into the air at an alarming rate and infect neighboring crops is downright chilling.

You don’t want mold on your cannabis crop. But unless you understand what you’re looking for, spotting molds (particularly bud rot) is tricky. It’s not as simple as spotting the green fuzz on the bread in the back of your fridge. 

When it comes to protecting your cultivation facility, you should prevent the outbreak from attacking your plants in the first place.

How do I stop mold in my grow room?

Cannabis thrives in environments mold and mildew love. Still, keeping parasitic fungi at bay is relatively simple if you maintain the proper environment. You can even grow strains designed to ward off mold.

Your best line of defense in mold prevention is understanding a few primary cannabis cultivation best practices. Keep reading to learn about a few of them. 

Keep the airflow going. 

Mold is present in the air at all times. And it doesn’t require much to proliferate. Containing the spread is an uphill battle once mold starts on its wind-blown path of destruction.

That’s why indoor cultivation facilities can benefit significantly from good airflow. Producing enough airflow to rustle leaves gently can make all the difference in keeping molds from settling and spreading. And if you add fans or an HVAC and air filtration system, you’ll also significantly reduce the chance of mold contamination. 

Control the humidity. 

Mold and mildew only need two elements to grow: moisture and organic material. You must keep humidity in check, especially if you cultivate in particularly moisture-rich environments. You should ensure that your relative humidity is no more than 70% (ideally, somewhere between 59% to 63%).

Anything higher, and you run the risk of trapping the moisture that mold needs to grow. You can use a humidor or dehumidifier to regulate excessive humidity. The only downside is that the equipment is pricey for small-scale cannabis cultivation facilities. But here’s a pro tip if money is tight: use inexpensive humidity packs inside your containers. 

Maintain a consistent temperature

Sixty-eight degrees (20 degrees celsius) is the ideal growing temperature for cannabis, and seventy-seven degrees (25 degrees celsius) is suitable for storage. Excessive heat locks in moisture, which leads to mold, and frigid temps can increase moisture exposure. 

Your grow room needs balance. 

Fans can level out temperatures, but if your grow room is too hot, you should consider venting the hot air outside. Also, you should install an air conditioner or evaporative cooler. Choosing the proper light schedules will also help you keep a consistent temp.

Store cannabis in a dark, dry place

How you store cannabis matters.

A cool, dark, dry storage environment will not only maintain the potency and flavor of your cannabis but will also keep out mold. Clean, airtight mason jars are a simple method to limit oxygen and moisture exposure. 

You should avoid plastic packaging because it can degrade crop quality. We also suggest that you keep your plants out of freezers and refrigerators – they’re an open invitation for moisture and mold. And if it’s in your budget, you can always consider investing in a humidor. 

Prune and trim your plants. 

You should diligently prune and trim your cannabis plants. Growing one large “Christmas tree” shaped bud makes the plant more susceptible to bud rot, especially if flowering during high humidity periods.

Regularly trimming your greens can eliminate the unnecessary plant matter that plays host to molds and mildew. Low-stress training (LST) can improve yields and prevent mold growth. LST is a simple bending/tying technique cultivators use to manipulate the plant’s height and shape. Also, this method is excellent for space and light distribution.

Testing your bud is essential.

Today’s cannabis industry is compliance-driven. Every legal state has regulations to ensure consumers get the cleanest, safest cannabis. Some states even inspect for total yeast and mold counts (TYMC) to detect fungus quantities. 

Of course, ingesting and inhaling moldy weed isn’t ideal. Moldy weed leaves consumers vulnerable to many ailments, from headaches and vomiting to acute lung infections.

Customers need to know that what they are purchasing is safe. And as we’ve noted before, third-party testing isn’t perfect. Breaking into the cannabis industry isn’t easy. Don’t throw your hard work, reputation, and licenses away with contaminant violations. 

GemmaCert can keep your cannabis safe and your business flourishing.