The 5 Best Ways To Check For Moldy Weed, Plus How To Avoid It

Nothing kills a buzz like moldy weed. It affects the potency, the smell, and the flavor of your favorite strain — and not in a good way.

Moldy weed can even cause some rather serious health problems, so it’s vital to know how to check your bud for rot and what to do if you find it.

In this article, the cannabis experts at Honest Marijuana tell you everything you need to know about moldy weed and give you tips on how to prevent mold growth in the first place.

How Does Mold Affect Your Health?

The two most common types of marijuana mold are:

  • Botrytis cinerea (a.k.a. bud rot)
  • Aspergillus

Bud rot is the least dangerous of the two, although it can still cause serious health problems, like lung damage.

Inhaling aspergillus, on the other hand, can cause infection, aspergilloma (ranging from cough to severe fatigue to bleeding airway), and even invasive pulmonary aspergillosis, which can be fatal if not treated properly.

Avoid both of these molds at all costs. The first step in keeping yourself safe is knowing what causes mold to grow.

What Causes Moldy Weed?

Oxygen

Mold, like most other organisms, needs oxygen to survive. But you can’t grow and store cannabis in a vacuum. That just won’t work.

You could try vacuum sealing your weed for long-term storage, but that’s definitely not convenient if you want to use those buds in the near future.

Instead, don’t worry too much about oxygen, and focus your efforts on the next cause of moldy weed.

High Humidity

Humidity is the number one cause of mold growth on marijuana plants.

As soon as the humidity around your pot plant passes a certain level (63 percent), mold can start to grow. All it needs is that moisture and a bit of oxygen and it’s off to the races.

Mold doesn’t even require light to grow — just oxygen and water. So you can store your pot in the deepest, darkest dungeon, but if there’s oxygen and high humidity, you’ll end up with moldy weed.

Lack Of Airflow

Mold spores thrive in tight conditions with low airflow.

In outdoor grow operations, the wind usually provides enough airflow to keep mold at bay. In indoor grow operations, fans keep the air circulating and prevent mold from taking hold.

When storing your weed — which is when most mold begins to grow — it’s essential to crack the lid or open the bag at least once a day to replace the stale oxygen with new.

That’s not a problem if you’re partaking of the weed on a daily basis. The simple act of retrieving the bud for your next smoke sesh supplies enough airflow to keep your cannabis mold-free for a short time (assuming the humidity is low enough).

Temperature

Temperature can also affect mold growth, but this variable is much more difficult to control because mold flourishes in the same range as humans.

If you want to ensure that mold won’t grow, you can keep the temperature around your weed below 40℉ or above 100℉. Is this realistic, though? No.

Sure, mold won’t grow, but both extreme cold and high heat will damage your cannabis buds in other ways.

A Note About Light

Astute readers will notice two seemingly contradictory facts throughout this article:

  1. Mold doesn’t need light to grow
  2. We recommend storing your weed in a dark place

What’s up with that? Well, light is basically heat.

You can control the ambient (a.k.a. surrounding) temperature of the space where you store your weed containers, but it’s extremely difficult to control the temperature inside those containers.

Even if you store your weed on your kitchen counter (e.g., in the sun) and you maintain a constant ambient of 70℉, light is going to raise the temperature inside that container by at least several degrees (if not more).

Those several degrees can quickly push the temperature of your weed into the mold-growing zone without you evening knowing it.

Unless you have some seriously high-tech storage devices that maintain their own internal environment, it’s best to store your weed in a cupboard or closet away from direct sunlight — not because mold needs light to grow, but because it needs the right temperature.

What Are The Best Ways To Check For Moldy Weed?

1) Look

The easiest way to check for moldy weed is to examine the bud with your naked eye. Common signs of mold include:

  • Cobweb-like material
  • Powdery appearance
  • Dark spots on green buds
  • Yellow fuzz
  • Grey fuzz
  • Slime

If you see any of these on your pot plant, consider it moldy.

2) Smell

Your weed will exhibit a wide variety of aromas — from berry to diesel fuel to skunk. But if you smell sweat or urine, your bud is probably going moldy.

That said, some people have more sensitive sniffers and will smell more of the weed fragrance even if mold is present. Additionally, some molds don’t produce any aroma until they’re further along in their development.

3) Feel

Healthy marijuana that is properly cured should feel dry and crispy. If your weed feels damp or spongy, it may be moldy.

Detecting mold on your marijuana takes practice and often involves all three of the tests above — look, smell, and feel.

But if you really want to be sure you don’t have moldy weed, you can take your tests to the next level by looking deeper and checking for recalls.

4) Look Deeper

If you own a microscope or can get your hands on one (they’re fairly cheap now), you can detect the first traces of mold before it becomes visible to the naked eye.

Even a jeweler’s loop or a strong magnifying glass can help you look deeper at the surface of your ganja flowers.

Mold produces structures (i.e., hyphae) that look nothing like any other part of the pot plant. If you see something out of the ordinary, it could be mold.

5) Check For Recalls

As a last resort, you can check media outlets and even the grower’s website (if they have one) to check for recalls due to moldy weed.

This may not be the most reliable way to check for moldy weed — because many issues like this go unreported — but it can be effective if the crop was large enough and shipped to multiple locations.

What Should You Do With Moldy Weed?

The only 100-percent safe way to “use” moldy weed is to get rid of it. Sorry.

But if you want to try recovering the plant matter for recreational or medicinal use, check out the first three suggestions below.

Decarboxylate

Decarboxylating moldy weed in your oven (instead of smoking it) can be an effective way of getting rid of the mold.

Most molds can’t survive above 140℉, so baking the plant matter in a 230℉ oven for 35 minutes is a great way to render the mold inactive.

From there, you can cook a batch of edibles or even try a concentrate.

Whip Up A Batch Of Concentrate

Once you’ve decarbed your weed, you can brew your own concentrate at home.

The chemicals (e.g., alcohol, butane, and others) kill most of what mold remains after the decarboxylation process and make your cannabis flowers useful again

Use A Water Pipe To Filter The Mold

When your dabs are ready to go, load them in a dab rig with a water filter at the bottom. Liquid can filter out up to 15 percent of the mold on a pot plant.

If you’ve run your moldy weed through a decarb process and then cooked up an extract with it, inhaling the vapor through a water filter should remove any trace amounts of mold still in the mix.

But it’s worth saying again: the only 100-percent safe way to “use” moldy weed is to get rid of it by recycling it as compost.

Recycle

If you discover mold on your marijuana, consider recycling it as compost.

Proper composting raises the temperature of the soil to around 170℉. This high temperature kills the mold and breaks down the plant matter so you can use it as soil for the next generation of cannabis plants.

If your compost doesn’t reach 140℉ to 170℉, the mold may survive and transfer to the new plant you’re trying to grow.

How Can You Avoid Moldy Weed?

Home-Grown Weed

If you grow your own weed, the best way to avoid mold is to grow, cure, and store it in the proper conditions. Temperature, light, and humidity are your three biggest concerns.

To prevent mold from forming, store your weed in a space with the following characteristics:

  • No direct sunlight
  • Temperature below 75℉
  • Humidity between 59 percent and 63 percent

A closet or small room with the right climate and humidity controls is ideal for this type of storage.

Even with your best efforts, mold may grow on your bud. The only surefire way to avoid moldy weed is to purchase it in a special container.

Store-Bought Weed

Mold can’t grow without oxygen, so by controlling this final variable, we can provide you with the purest, safest cannabis on the market today.