Prevent damping-off disease with sanitation and airflow

Damping-off is a fungal disease where seedlings suddenly collapse at the soil line, with stems turning brown and mushy. It spreads fast and can wipe out an entire tray overnight. Prevention is essential because there's no cure once it starts.

Prevention Steps

1. Sanitize trays between cycles with a diluted bleach solution (1 tbsp per liter) or hydrogen peroxide
2. Use fresh growing medium every time — never reuse spent soil or mats
3. Don't overwater — damp, not soggy, is the target
4. Ensure airflow — a fan on low eliminates the stagnant humid conditions fungi love
5. Don't overseed — dense sowing creates a moisture trap at the base

Tips

• If you see one collapsed seedling, check the whole tray immediately
• Remove affected areas and increase airflow — you may save the rest
• Damping-off is more common in warm, humid conditions above 27°C