Plant Parenting: Tips for Avoiding Damping Off in Seedlings

January 17, 2020

Damping Off Disease

Damping off is a disease that is extremely frustrating for seed starters. It's usually a combination of several soil borne pathogens that move in quickly to take down seedlings as they are germinating. If your young seedlings turn brown or black at the base of the stem, then topple over, your you see mold-like growth on your seedlings, damping off may have set in. Typically, properly managing and balancing moisture is the key to preventing damping off.

Dealing with Damping Off

There are a few tips you can employ to decrease your chances of the disease attacking your seedlings:

  • Avoid adding fertilizer to your seeds before or right after they germinate. Fertilizers can encourage fungus and mold growth.
  • Commercial growers will use synthetic chemicals to prevent damping off, but you probably don’t want to do this in your home or for edible crops. A handy alternative is to water your seedlings with a hydrogen peroxide solution. Hydrogen peroxide oxygenates the soil, which kills off many fungi and bacteria. Mix 1 teaspoon of hydrogen peroxide to 2 cups of water and then use the solution to water or mist your seedlings.
  • Keeping excess water off the foliage will help reduce fungal disease problems. As seedlings grow, you’re best to shift from a spray bottle—which wets the foliage—to small watering cans or squirt bottles, so you can deliver water directly to the root zone without getting water on the foliage.
  • Don't leave your germination humidity dome on too long. Once seedlings have germinated and are developing true leaves, you can usually remove the humidity dome so excess moisture doesn't build up and breed disease.

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