This week's word of the week is DAMPING-OFF. Dictionary.com defines damping-off as a disease of seedlings, occurring either before or immediately after emerging from the soil, characterized by rotting of the stem at soil level and eventual collapse of the plant, caused by any of several soil fungi.
As gardeners eagerly await the official beginning of the spring season, there will be lots of seeds being sowed at home, or commercially in greenhouses across Ohio to support gardeners efforts in growing food, supporting pollinators and creating beauty in gardens and landscapes across the buckeye state.
Damping-off can affect many vegetables and flowers and is caused by a fungus or mold. These pathogens typically thrive in a cool and wet conditions. It is important to be aware of the temperature, especially in the media where the seedings are being started. Monitoring the amount of water the seeds, and ultimately seedlings receive as they grow is so important. Overwatering can be problematic.
While there are great factsheets that cover damping-off, I thought that the University of Minnesota Extension has a great educational resource, "How to Prevent Seedling Damping-Off." The factsheet covers: what damping-off is, identifying symptoms, causes of the disease, prevention and mangement of the disease, and a valuable chart that highlights several edible crops and the minimum soil temperature, and the best soil temperature.
You can find that resource online at: https://extension.umn.edu/solve-problem/how-prevent-seedling-damping
Once damping-off is identifed, it usually 'spreads' or moves through adjacent seedlings in the same seed starting tray, or those in close proximity. Seedlings will rarely survive the infection. Fungi, Rhizoctonia spp. and Fusarium spp., and water mold Pythium spp. are commonly the pathogens responsible for seedlings damping-off.
Included in the University of Minnesota Extension's factsheet are several points to help gardeners and growers identify symptoms.
- Seedlings fail to emerge from the soil.
- Cotyledons (the first leaves produced by a seedling) and seedling stems are water soaked, soft, mushy and may be discolored gray to brown.
- Seedling stems are thin, almost thread-like, where infected.
- Young leaves wilt and turn green-gray to brown.
- Roots are absent, stunted or have grayish-brown sunken spots.
- Fluffy white cobweb-like growth on infeted plant parts under high humidity.
Once present, there are some important steps that gardeners and growers must follow to ensure the disease doesn't continue to spread. Pathogens can survive on pots, tools and in planting media, and must be cleaned to avoid continued spread not just in the current season, but into the future.
Damping-off can also occur when direct seedling outdoors. It is more prevalent when weather conditions, and ultimately soil conditions, are cool and wet.
Good luck this seedling season and we hope that future is damping-off free!