Damping Off: the Killer of Seedlings

You had good germination and the seedlings are popping out of the soil. The next day you check and the seedlings are starting to flop over. What happened? The most likely cause is damping off.

What is damping off? Simply put damping off is the death or weakening of seedlings by fungus or growing conditions. It is often caused by the fungus called Rhizoctonia spp. and Fusarium spp., along with the water mold Pythiumspp (Source). Other factors that can cause damping off are cool and wet conditions. Seedlings like it wet, but not sopping wet and they like warm temperatures. Though it should be noted fungus and mold grows in warm wet conditions. It's a very delicate balancing act: just wet and just warm enough.

How do you prevent damping off? I sprinkle cinnamon on top of the soil and water with a weak chamomile tea. I will fill up jugs of water and allow them to sit a few days before watering my seedlings. In this jugs I will throw in a chamomile tea bag. Make sure water is at room temperature or warmer. Provide 16 hours of light from grow lights a day and make sure the lights are 2-3 inches from the trays/plants. Also once most of the seedlings are sprouting put a gentle breeze on them and thin them or re pot when they are big enough.

Another way to prevent damping off is to make sure you are using potting soil or a seed starting soil and disinfecting all your containers/pots, tools, lights, and shelving units at the end of the season. If you have a room dedicated to starting seeds do a thorough deep clean and disinfect everything. It is important to note that once damping off starts there is nothing that can be done so prevention is key.