What Is Damping Off?

What is damping-off?

Damping-off is the sudden death of young seedlings caused by a fungus that thrives in overly damp and cool conditions. When damping-off occurs, seedling stems rot at (or slightly below) soil surface level, causing them to wilt and die. Damping-off is a common problem that many gardeners face when trying to grow from seed, and can occur in a wide range of plants, from vegetables and herbs to ornamental flowers. Fortunately, damping-off only affects seedlings for a short period of time following germination. Once seedlings have established stems, leaves, and a well-developed root system, they are better able to naturally resist the fungus that causes damping-off.

How to identify damping-off:

Damping-off is a quick-acting condition which occurs seemingly overnight; one day you have a healthy batch of seedlings, and the next day they look as though they were pinched off at soil surface level. Damping-off can be difficult to identify at its early stages, but there are some telltale signs to look out for. The first sign of damping off is often the appearance of water-soaked spots near the base of the stem of the seedling. As the disease progresses, the stem becomes soft, eventually collapsing and causing the seedling to wilt and die. Seedlings will appear grey and stringy and might also look wet and mushy.

What to do if damping-off occurs:

Once damping-off occurs, the seedlings cannot recover. Seedlings and growing medium should be properly disposed of, and the planter should be soaked in a 10% bleach solution for 30 minutes and rinsed thoroughly before next use.

How to prevent damping off:

Water mindfully. Avoid overwatering seedlings, as excess moisture can create the perfect environment for fungal growth. Morning is the best time to water, as this gives excess moisture a chance to absorb and evaporate from seedlings and growing medium, instead of sitting overnight. Water seedlings when the surface of the growing medium begins to dry. Ideal moisture level for growing medium is best described as evenly moist (like a wrung-out washcloth or sponge), never soggy or wet.

Grow with the flow! Air circulation is just as important as sunshine, water, and growing medium! Proper airflow helps plants develop strong growth all while keeping pests and fungal issues at bay. Use a fan or open a window to promote good air circulation in your growing area.

Don’t overdo it. Overcrowding seedlings can create conditions that favor the development of the fungus that causes damping-off. When sowing, space seeds evenly to allow for adequate airflow between sprouted seedlings and across the surface of the growing medium.

Save up for a rainy day. If you are planting in a small container, it’s ok to save your extra seeds for a later date! As long as they are properly stored (cool, dark, and dry in an airtight container) seeds can last for several seasons.