Exploring Mold on Weed: Trigger
and Remedies

Moldy weed is one of, if not the most common issue when growing, and storing weed. There are a few different types of mold on weed that can infect your plant growth, for many different reasons.

Through this guide, we’ll cover the basics and help you prevent mold from infecting your plants and growing in your storage jars, and go over how act preventatively so you don’t get moldy weed!

2 Common Types of Mold on Weed While Growing

1. Powdery Mildew

There are 2 main types of mold that can grow on your weed plant, or finished product. The most common is “Powdery Mildew”, or often referred to as “PM.”

What Does Powdery Mildew Look Like?

What Does Powdery Mildew Look Like?

As the name suggests, this is a white powdery-looking mold that most commonly infects the weed plant while it is still growing.

Causes

PM is usually caused by low air movement, high humidity, and fungal content in the grow environment—sometimes these factors are a byproduct of an overcrowded grow space.

PM can be tough to get rid of, so it is much better to act early, and preventatively, to make sure you don’t get this type of mold on weed plants. Make sure to scout your grow daily for mold or pest control, feed a balanced diet to the plant, try not to overdue any one aspect (feed, watering, light, co2, environmental factors) as cannabis thrives with balance, create a spray or “IPM” schedule to ensure the plants don’t get infected or infested.

If you feel not confident about managing all these factors on your own, don't worry. You can rely on automated indoor grow tent kits with climate control features. These all-in-one solutions will handle everything we've covered, and in turn prevent mold on weed right from the start.

How to Get Rid of PM?

As mentioned previously, PM can be tricky to get rid of; it is a systemic fungal disease that once seen on the leaves/stems of the plant, the internals of the plant have already been infected for sometime.

Growers usually assume, because PM is caused by high humidity, that is best to lower the humidity of the grow space to try and get rid of. What happens when you lower the humidity? Well, the pm will sporulate when the humidity gets low; it basically turns into a very fine particle-powder and gets in the air, and can infect many more plants.

The best plan of action to mitigate powder mildew is:

• Raise the PH of the plant: Feed/Water your weed plants with a higher ph solution! Low pH causes the plant to attract illness and diseases;
• Spray with organic fungicides/inoculants and microbial teas: Microbes and inoculants will support the immune system of weed plants. These microbial bacteria work tirelessly to combat mold mildew;
• Spray with a high pH: Keep the spray's pH around 6.6. Higher PH kills PM!

2. Botrytis

The next most common type of mold on weed is “Botrytis,” most commonly known as “Bud Rot” or “Grey Mold.” Cannabis bud rot is an also a fungal systemic disease, and will live in the internals of the plant. It will often appear in the later or final weeks of flowering stage, and can have a few different appearances.

What Does Bud Rot Look Like?

Image via Dutch-Headshop

It commonly shows up in the middle of very large or dense flowers, and can give the middle of the flower a dark discoloration. The grey mold may also grow on the outside of the buds, and have a cottony, or webby look to it—it can sometimes even be mistaken for spider mite webs!

Causes

Why does grey mold grow on weed? Well, it can be caused by a few different factors, like:

• High humidity: Similar to PM, high humidity creates favorable conditions for the growth and spread of mold on weed.
• Overwatering: When the plant receives too much water, it can cause cells to burst, which can dramatically weaken the plants' immune system, and the botrytis will take advantage of the the plants compromised health.
  
  Overwatered cannabis is common in the final stage of flowering, as many growers like to flush the plants and will administer way too much water in attempt to flush out the medium. Over watering and poor drainage can also cause the excess moisture in the plant which can accelerate the growth of mold and fungus.
  
• Over crowding of plants: Once the air flow between the plants and canopy is limited, that can cause moisture retention, and create a vapor barrier which leads to slowing of transpiration and excess storage of water.
  

How to Get Rid of Botrytis?

Unlike PM, Bud Rot can’t be prayed away or amended, so it is crucial to make sure the plants are receiving good airflow (by installing a fan or other ventilation system) throughout the canopy, and proper watering techniques are being practiced. The medium needs to dry back before the next watering/feeding is administered.

Moldy Weed Caused By Improper Storage

Mold can also grow on your weed while curing or being stored! This is most commonly caused by improper storage conditions, or improperly dried flowers.

Make sure the buds are fully dried before jarring and curing. To test if they're dried enough, you want that pronounced “snap” from the branches before you move the product into storage bags/jars. You will also need to burp the flowers while curing:

• Open the jars up a few times a day and move the buds around to allow any excess moisture to escape;- Close the bags/jars back up;
• Close the bags/jars back up;
• Repeat in a few hours!

Many people like to add humidity packs when storing weed buds, but this may also cause high moisture levels if the jar/bag isn’t being opened regularly. If you plan on storing the buds for a sustained period of time, it’s best to not add humidity packs.

How to Get Rid of Mold on Your Dried Buds?

If you open your bag/jar and notice a musty smell (mildew/standing water/rotting vegetation), or you notice the buds have a white-cottony substance, or dark discoloration- chances are your dried buds have mold growing on them.

If you find any buds with mold, throw them out! There is really no way to treat moldy weed, or get rid of the mold.

Some people will attempt to wash the moldy weed with some crazy concoction, or trim away the mold, but there's a high likelihood that not all of it has been removed.

What Happens If You Smoke Weed with Mold?

There can be serious health risks associated with smoking moldy weed, such as:

• throat and lung irritation
• respiratory infections
• allergic reactions
• fungal infections
• ingestion of mycotoxins that can lead to liver or kidney issues

In our previous article, we discussed why smoking weed stems is not advisable. And similarly, the answer remians the same when it comes to smoking weed with mold. It is simply not worth the risk to do it! Make sure you dry and store your bud properly. It is the best and easiest way to avoid mold infecting or growing on your buds!

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