Damping-off is the death of young seedlings, either after emergence or after transplanting. This is noticed through the stem of the plant turning brown or black at soil level and then withering causing death of the plant.
The condition is prevalent in cold, wet soils or in cool, damp weather. Crowding of seedlings, over watering, lack of air circulation or contaminated (pots, soil or water) can increase the chances of plants being affected by Damping-off.
How to Prevent Damping Off
- Use a sterile potting mix, rather than soil from your garden. The funguses and moulds that cause damping off can live in the soil and outdoor garden soil can harbour all kinds of fungus spores.
- Start with clean pots. Even the small amount of soil clinging to plant pots is enough to provide a safe harbour for fungal spores. If reusing pots, sterilize in 1-part bleach to 10 parts water.
- Plant your seeds at the proper depth so they don't have to work so hard to germinate. Don’t bury the plant’s crown.
- Don’t crowd your seedlings. Be sure to leave room between them for air circulation. Fungal diseases and mould favour damp conditions.
- Water seedlings from the bottom, by placing the container in a tray of water. This keeps the seedling itself dry and less susceptible.
- Don’t over water your seedlings or leave them sitting in water. Drain off any excess.
- Give your seedlings plenty of heat and light, so they germinate and grow quickly. Damping off only affects seedlings. If you can get them past the seedling stage, they're safe.
- Remove any affected plants or trays of plants immediately. Damping off will quickly spread to nearby plants.