Damping off (or damping-off) is a horticultural disease or condition, caused by several different pathogens that kill or weaken seeds or seedlings before or after they germinate. It is most prevalent in wet and cool conditions.

When does damping-off happen?

Damping off is a term used for the sudden death of new plant seedlings. 1 It can be caused by any of a handful of fungal diseases, including the pathogens Pythium, Phytophthora, Rhizoctonia spp., Fusarium spp., Sclerotinia, and Botrytis.

How does damping-off occur?

Damping off affects many vegetables and flowers. It is caused by a fungus or mold that thrive in cool, wet conditions. It is most common in young seedlings. Often large sections or whole trays of seedlings are killed.