Sick Seedlings

Starting seeds indoors is always fun, but sometimes it can be disheartening, especially for beginners when newly sprouted seeds begin to grow and then overnight the seed tray looks like a mini tornado swept through. Seedlings are left horizontal, dead and dying, and appear to have had their stems pinched right at the soil level.

What happened is a disease called Damping Off. It’s caused by any of a number of fungi that occur in all soils and tends to attack slow-growing or weak plants. As the name suggests, the disease prefers damp conditions, exactly what is required for growing seedlings. There used to be commercial fungicides designed specifically to control damping off but they are no longer available to home gardeners.  A few precautions, however, can reduce the likelihood of damping off. 

Use clean containers and a soill-free potting mix for starting seeds. Fill seed trays or pots right to the brim with the soil and avoid spreading seeds too densely. This allows for more air movement at the surface. A small fan blowing across seedlings can be helpful, but keep in mind this can rapidly dry out the soil.

If you start your seeds under a plastic cover, which is the usual way, remove the cover as soon as germination has taken place as fungal growth loves the high humidity under the cover. For the same reason don’t overwater and avoid watering from above as this ensures the soil surface remains damp and conducive to fungal growth.

Many untested suggestions such as sprinkling cinnamon on the soil surface have made the rounds online, and though cinnamon does have anti-fungal properties, the only hard evidence is on cinnamon oil, rather than the powder (which may not be pure cinnamon), so I’d save it for the hot chocolate and apple pie.