Knowing When Your Crop is Beyond Saving from Pests and Disease

By Kent Gruetzmacher
Published: December 13, 2022
Key Takeaways

Whether it be spider mites, powdery mildew, or botrytis, it can be tough knowing when your cannabis plants are too diseased to save. With a bit of research, you can uncover some telltale indicators that will let you know when your crop is simply beyond help.

When it comes to dealing with bugs and pathogens, it often takes years of experience to effectively diagnose and treat issues. Many beginner growers don’t have the confidence it takes to destroy a crop when it reaches a certain disease threshold.

Becoming a good cannabis grower is all about trial and error. Even the most skilled growers have to fail a few times before they succeed. While it is always tough to deal with diseased crops requiring you to destroy plants, you should take these opportunities to become a better grower.


The First Step is to Diagnose the Issue

The first step in understanding when your cannabis plants are too diseased to save is diagnosing the problem. All things considered, before you can make any important decisions about whether or not to keep your crop, you first need to understand exactly what is wrong.

While certain diseases and deficiencies are easy to diagnose, others are more challenging. The best way to set yourself up for success in the future is to research common molds, mildews, bugs, and imbalances that affect cannabis plants.

Once you know the type of disease you are dealing with, you have the information needed to aid in your decision making on whether to save or destroy a crop.

What is the Threshold with Spider Mites?

spider mites


Spider mites are one of the most common bugs causing problems for cannabis growers. Whether you are growing indoors or outdoors, these pesky insects always seem to find their way into your cannabis garden.

Spider mites first exhibit themselves as little white dots on the top sides of leaves. When you find this discoloration, turn the leaf upside down and you will discover spider mites inhabiting the undersides of the leaves. Because spider mites are so small, they often resemble dark pieces of dirt — until they start moving around.

A good indicator that a plant isn’t salvageable from a spider mite infestation are webs spun around branches and flowers. For a spider mite infestation to have progressed this far, they had to have gone unchecked for a significant amount of time. You can rest assured your garden has a healthy spider mite population that is likely impossible to fight without destroying your plants.

How Much Powdery Mildew is Too Much?

powdery mildew on a cannabis plant

Powdery mildew is a pervasive pathogen that can destroy a cannabis crop if left unchecked. The primary cause for powdery mildew is overly humid conditions and poor airflow in the garden. When such environmental imbalances persist, powdery mildew has the chance to establish itself on plants.

Powdery mildew is easy to identify as white, fuzzy spots on the leaves, stems, and flowers of cannabis plants. Even more, while bugs like spider mites leave small indentations in leaves, powdery mildew protrudes off the leaf surface.


The ability to deal with powdery mildew effectively is largely tied to the growth phase of your cannabis garden. If you discover powdery mildew during vegetative growth, you can likely get the problem under control with an organic fungicide. However, if you have a powdery mildew outbreak during flowering and the pathogen infiltrates the insides of buds, they must be destroyed.

As long as powdery mildew doesn’t make its way inside the flowers, you can salvage your plants from this common disease.

Identifying and Preventing Mold in Harvested Buds
Growing Cannabis in Humid Conditions: Mold-Resistant Strains
10 Common Cannabis Leaf Problems and How to Fix Them


Can I Save My Cannabis Garden from Botrytis?

botrytis on a cannabis plant

Botrytis is a mold commonly referred to as “bud rot.” Due to the rapid speed that botrytis can spread through a garden, it is one of the most dreaded pathogens for hobbyist growers and commercial producers alike. Like powdery mildew, botrytis comes about when overly humid conditions persist in your garden.

You can identify botrytis with yellowing sugar leaves that protrude from the insides of flowers. When mold begins to grow on the inside of buds, it kills these sugar leaves, which are then noticeable from the outside. Unfortunately, once you have identified botrytis, it has likely already done significant damage to your crop. When you peer into one of the damaged flowers, you will find grey and brown mold, as well as rotten plant material.

Once cannabis plant tissue has come in contact with botrytis, it is no longer salvageable, so you should always keep a close eye on flowering plants so you can catch an outbreak early on. When you find botrytis, carefully remove all the mold and damaged plant material. Oftentimes, this heartbreaking chore involves dissecting your prize colas.

If you notice that a bud is over one-third infected with botrytis, you should destroy the flower. Once you have removed such a large portion of the bud, there simply isn’t enough left to work with. It’s also a good idea to consider harvesting early to slow any further damage.

Dealing with diseased cannabis plants is one of the toughest parts of being a grower. Nonetheless, each challenge with cannabis growing can also be seen as a great learning opportunity if viewed with the right perspective. If you have to undertake the unfortunate task of destroying plants, be sure to note what went wrong so you don’t repeat the problem. The more experience you gain growing cannabis, the more comfortable you will become dealing with diseases.

For many people, the idea of destroying plants after putting so much passion and energy into growing a crop is too much to bear. However, you will want to be 100 percent sure your plants are a lost cause before you decide to remove them from your garden.


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Written by Kent Gruetzmacher | Writer, Owner of KCG Content

Profile Picture of Kent Gruetzmacher

Kent Gruetzmacher MFA is a Colorado-based writer and owner of the writing and marketing firm KCG Content. Kent has been working in the cannabis and hydroponics space for over a decade. Beginning in California in 2009, he has held positions in cultivation, operations, marketing, and business development. Looking specifically to writing, Kent has worked with many of the leading publications and marketing agencies in the cannabis space. His writing has been recognized by such icons as Steve D’Angelo and Rick Simpson.

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