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Bud rot is one of the most feared diseases in cannabis cultivation. Also known as bud rot or botrytis, this fungal infection usually occurs during the flowering stage and destroys buds from the inside out. In this article, you will learn how bud rot develops, how to recognize it early, and which measures are effective to stop its spread and protect future harvests.
Quick diagnosis: Bud rot is a fungal flower rot promoted by high humidity and insufficient air circulation. Infected buds cannot be saved and must be removed immediately.
What is bud rot?
Bud rot is caused by the fungus Botrytis cinerea, which becomes especially active under humid conditions. The fungus primarily attacks dense flower clusters and spreads from the inside outward. In many cases, the infestation remains unnoticed for a long time because the outer structure of the bud initially appears healthy.
In cannabis cultivation, bud rot is considered one of the most serious problems, as it can render entire plants or harvests unusable within a short period of time.
Identifying bud rot – typical symptoms
- Dark or brown areas inside the bud
- Soft, mushy texture of the flowers
- Gray, dusty mold in advanced stages
- Dead flower sections, often without earlier visible warning signs
As soon as one of these signs becomes visible, immediate action is essential.
Causes of bud rot
Bud rot almost always develops due to a combination of unfavorable environmental conditions:
- excessively high humidity, especially during flowering
- insufficient air movement within the plants
- dense flower structures without adequate drying
- temperature fluctuations leading to condensation and dew point formation
Humid nights, stagnant air, and poorly ventilated grow spaces are particularly critical.
Preventing and limiting bud rot
Bud rot cannot be cured. The goal of all measures is to stop its spread and prevent future infestations.
Controlling humidity
Keep humidity consistently low during the flowering phase. Levels above 50 percent significantly increase the risk. In many setups, the use of dehumidifiers is highly recommended.
Improving air circulation
Even and consistent airflow prevents moist microclimates inside the buds. Fans should be positioned to eliminate stagnant air without causing direct stress to the plants.
Plant care and hygiene
Infected buds must be removed immediately and generously. Tools should be cleaned afterward to prevent the spread of fungal spores. Excessively dense foliage can also be carefully thinned to improve airflow.
Further visual diagnosis:
Cannabis Pests & Diseases
Conclusion:
Bud rot is a serious fungal disease that should never be underestimated in cannabis cultivation. Early detection, strict climate control, and the immediate removal of infected buds are the only effective measures. Understanding bud rot is the key to preventing it in the long term.