Bud Rot: Don't Let it Destroy Your Harvest

Bud Rot, also known as gray mold, is a destructive fungus that can turn a whole harvest into a total loss. Considering the severity of gray mold, it will always be a hot topic for growing, drying, and storing your hemp flower. Thankfully, you can prevent gray mold if proper action is taken throughout your Cannabis plants' life cycle, especially when it is close to harvest time. Learn more at the Canvast blog.

Bud Rot, also known as gray mold, is a destructive fungus that can turn a whole harvest into a total loss. Considering the severity of gray mold, it will always be a hot topic for growing, drying, and storing your hemp flower. 

Thankfully, you can prevent gray mold if proper action is taken throughout your Cannabis plants' lifecycle, especially when it is close to harvest time. 

In this article, I'll cover how Dr. Zymes Eliminator, Essentria IC-3, and Biosafe Zerotol make a fantastic trio for keeping mold out of your dry rooms in your post-harvest season without risking chemical residues. 

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What is Bud Rot

Bud Rot is caused by the fungus Botrytis cinerea and has been one of Cannabis and hemp plants' most destructive pests for decades. 

You can identify Bud Rot by its gray, fuzzy appearance, usually accompanied by the browning of leaves and flowers attached to the same affected branch. Abnormal growth and spots are also an early sign of Bud Rot. 

What is Bud Rot

This type of mold is a moisture and humidity loving fungus that thrives in cold climates with low air circulation. 

It's dusty gray spores are spread via direct contact with the plant and can travel through the wind, water, people, and animals. 

Bud Rot occurs during harvest season when plants are at their maximum, and buds are packed tightly together in most outdoor or greenhouse scenarios. 

Also, caterpillars and grasshoppers are a significant problem in outdoor and greenhouse hemp operations. 

These insects eat into the plant, leaving dead plant material and frass (insect droppings) behind, a perfect breeding ground for mold. 

In this case, Bud Rot is the secondary pest after the caterpillar, and both are incredibly destructive. 

Canvast Flower is free of all contaminants 


Why Preventing Bud Rot Matters

If you harvest hemp flower with even small amounts of Bud Rot and bring them into your dry room, you risk getting mold on ALL of the flower in that drying space. 

The whole purpose of a dry room is to remove moisture from the freshly harvested flowers. Bringing in Bud Rot into a room can allow the fungus to spread to other flower that is still moist and begin to colonize in as quickly as 12 hours. 

Many buyers and processors now require microbial/mold testing on flower that they purchase. You risk failing these tests once mold enters your drying space! 

Your goal should be to eliminate the problem while it is still in the field to prevent Bud Rot altogether. 


How to Cure Bud Rot 

There is a vast and overwhelming amount of horticultural products and practices out there that supposedly "cure" Bud Rot. Anyone experienced in growing Cannabis plants will know that there is no one magical solution. 

However, there certainly are multiple methods and products that can almost guarantee that you will be free of Bud Rot if you are persistent and plan. 

The best defense against Bud Rot is to plant your rows with proper spacing for airflow for good circulation and air filtration - if growing indoors. 

That said, healthy plants play a crucial role in your plants' natural defenses, so make sure your nutrient program is proven to be successful. 


Be sure to prune dead/rotted flowers you find and sanitize your equipment regularly.

When insects and Bud Rot inevitably strike, a few products are proven to work for Cannabis/Hemp without the risk of chemical residues or burns on your precious flower. 

Essentria IC-3 is an excellent insecticide for tackling insects and mites before they leave their damage and droppings. If you prevent the bugs, you can prevent the mold that they cause! It is a blend of botanically extracted ingredients (mostly essential oils) that are natural and can even have an anti-mold effect on its own. It also doubles as a product that can be used in your drying room to sanitize and kill bugs that nest in your harvest!

Purchase Essentria IC-3 

Dr. Zymes Eliminator is another fantastic all-around product: insecticide, miticide, fungicide, and antibacterial. It is a mixture of plant-derived Citric Acid from a fermentation process. It is combined with other biologically stimulating ingredients formulated to keep your plants pest and mold-free. Dr. Zymes is also OMRI listed and friendly for organic growers and can be applied on the day of harvest! Just like the other two products listed here, Dr. Zymes can double as a spray for cleaning and sanitizing your harvest facility/dry rooms. I've personally battled Bud Rot many times and have had fantastic results by rotating Dr. Zymes Eliminator with BioSafe ZeroTol.

Purchase Dr. Zymes Essentria IC-3

BioSafe ZeroTol has proven to be one of the essential products in my arsenal as a Hemp grower. It is essentially a mixture of food-grade hydrogen peroxide and peroxyacetic acid, both well known and safe products if used correctly. ZeroTol is a powerful broad-spectrum bactericide and fungicide that kills algae, bacteria, fungi, and their spores on contact. It's a PERFECT solution for getting rid of Bud Rot in your gardens and sanitizing your plants just before harvest. There is no REI for this product, and can also be sprayed on the day of harvest to prevent mold as your flowers hang to dry! 

Purchase BioSafe ZeroTol

You can also use ZeroTol as an anti-fungal root drench for your plants. Use it as a dip for sanitizing your tools or a spray for sanitizing your grow/dry rooms and harvest facilities. I spray my plants with ZeroTol the morning of or day before harvest to prevent the Bud Rot from entering my drying facilities. 


It is easy to get overwhelmed by the number of pests and diseases that can affect your hemp plants. Bud Rot has proven itself to be one of the most destructive pests in the hemp industry. The key is to know your enemy and stay persistent in the fields before it is time to harvest your plants. 

A full spectrum rotation of horticultural practices and products is the best way to keep your plants clean and free of Bud Rot/gray mold. Bring clean plants into a clean drying facility, and you will benefit. Essentria IC-3, Dr. Zymes Eliminator, and BioSafe Zerotol that your plants need to prevent a moldy, low-quality harvest. Rotation of multiple products is the key to keeping pests at bay. 

Having multi-use products is good for your plants and easy on your budget. Spend time learning these products and putting a plan in place. As we say at Canvast "an ounce of prevention is worth a pound of cure."





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