If you're a cannabis grower, few things are more heartbreaking than discovering bud rot deep in your colas. It can quietly destroy your flowers from the inside out, and by the time you notice it, you’ve already lost precious yield. This guide covers everything you need to know — what causes bud rot, how to spot the early signs, treatment strategies, and crucial steps to prevent it from ever taking hold in your grow.
Whether you're growing indoors or outdoors, bud rot (technically known as botrytis cinerea) is an enemy you’ll want to understand — and beat.
Bud rot, also known as botrytis, is a gray mold that attacks dense cannabis flowers. It usually starts from the inside of the bud, making it tough to catch until it's already caused irreversible damage. The fungus thrives in moist, humid conditions and can spread rapidly from one cola to the next.
Key symptoms include:
Bud rot thrives under very specific conditions — and unfortunately, those conditions are often found in grow rooms or outdoor gardens without proper airflow or humidity control.
Common causes of bud rot include:
Post-harvest bud rot can also occur if buds are not dried and cured properly. Learn the right way to cure your cannabis and avoid post-harvest rot by checking out our Beginner's Guide to Harvest, Dry, and Cure.
By the time bud rot is visible on the outside of your nugs, it’s already spread internally. That’s why early detection is key. Here’s what to look for:
Using a microscope or jeweler’s loupe, you may spot spore filaments if you suspect infection early. It’s worth doing regular inspections, especially during flowering.
Unfortunately, once bud rot has infected a bud, it cannot be saved. Here’s what you can do:
Only the uninfected buds that were not directly in contact with mold may be safe. However, err on the side of caution — smoking moldy weed can cause respiratory issues. Never attempt to clean or “wash” bud rot away and still consume it.
The best way to win the fight against bud rot is to prevent it entirely. Here’s how:
Some growers incorporate organic antifungal sprays during early flowering. For a long-term air purification solution, consider the ProGuard Defender DXB Mini, which reduces airborne pathogens and mold spores.
Even if you harvest healthy buds, improper drying and curing can lead to late-stage bud rot. Always dry buds in a room with:
Once dried, monitor curing jars or bins regularly for moisture buildup or odd smells — mold can still develop in overly moist conditions.
Bud rot can devastate an entire harvest if left unchecked. But with the right tools, knowledge, and preventative steps, you can avoid it entirely. Regular inspections, strict humidity control, and proper airflow are your best weapons in the fight against this destructive fungus.
If you’re serious about preserving your grow, upgrade your setup with tools like Anden’s commercial-grade dehumidifiers or purifiers like the ProGuard Defender. Prevention beats treatment every time.
