Grey Mould (Botrytis)
A fuzzy grey fungus that rots soft leaves, stems and flowers in cool, damp, still air.
🔍 How to spot it
A soft, fuzzy grey or brown mould, most often on dying flowers, damaged leaves and soft stems. Affected tissue turns brown, soft and slimy, and a puff of dusty spores rises if you disturb it. It thrives in cool, humid, poorly ventilated spaces.
💥 The damage it does
Botrytis moves in on dead or damaged tissue and then spreads into healthy growth, rotting flowers, buds and soft stems. In a cool, damp greenhouse or crowded windowsill it can spread fast and ruin blooms and cuttings.
🧴 How to treat it
Cut out all affected growth well into clean tissue and bin it, then dramatically improve airflow and lower the humidity. Remove dead leaves and spent flowers promptly, since they are the entry point, and avoid misting until the outbreak is under control.
🛡️ How to prevent it
Keep air moving, avoid overcrowding, and clear away dead and dying material before the fungus can colonise it. Water in the morning so surfaces dry out, and ventilate cool, damp rooms and greenhouses.
🌿 Plants that get grey mould (botrytis)
Worst on soft-stemmed plants, flowers, seedlings and greenhouse plants. These 37 profiled plants name it in their own troubleshooting notes:
Houseplants 8
Garden 29
Struggling to save a plant? The plant rescue guides walk through recovery step by step, and the problem solver works backwards from a symptom. This is general growing advice, not a diagnosis for a specific plant.