Bud Rot
Definition: Bud rot is a fungal disease, usually caused by the gray mold Botrytis cinerea, that rots cannabis flowers from the inside out. It thrives in cool, humid conditions late in flowering, when buds are dense and moist. Infected buds turn brown and mushy, then develop gray, fuzzy mold. Moldy cannabis shouldn’t be smoked or eaten.
What Causes Bud Rot?
Spores of Botrytis cinerea are everywhere in the environment. They take hold when humidity is high, airflow is poor, and temperatures are cool, especially inside thick, tightly packed colas where moisture gets trapped. Rain, heavy dew, and crowded indoor grows all raise the risk.
How Do You Spot Bud Rot?
- Wilted or browning pistils and sugar leaves on an otherwise healthy bud
- Brown, gray, or black mushy spots deep inside the bud
- Gray, fuzzy, web-like mold once it progresses
- A musty, damp smell
Because it starts inside the bud, it’s easy to miss until it has spread. Gently open suspicious buds to check.
How Do You Prevent Bud Rot?
- Keep humidity lower during late flowering, especially at night
- Improve airflow with fans and spacing, and remove excess leaves
- Avoid overwatering and watering late in the day
- Outdoors, choose mold-resistant genetics in wet climates
Is It Safe to Smoke Weed With Bud Rot?
No. Remove and discard infected buds immediately, along with nearby affected material, to keep spores from spreading. Inhaling moldy cannabis can irritate the lungs and is especially risky for people with weakened immune systems or allergies. Licensed products are tested for microbial contamination before sale.
Related terms: Botrytis Cinerea, Myclobutanil, Clone, Trichomes
Sources: National Institute on Drug Abuse: Cannabis (Marijuana).
