Warm spring weather results in the rapid growth of yard and garden plants, particularly seedlings. If cold, wet weather follows, damping-off disease can be a problem. This disease is caused by fungi that rot the seedling stem right at the soil line and, overnight, the infected seedlings can topple over and die. Damping-off can also kill seedlings before they break through the soil. Seedlings growing in containers are more susceptible than those growing outdoors in the garden.
To help prevent damping-off, grow seedlings in well-drained soil with plenty of light and air circulation. Don't allow the seedlings to crowd each other, as the lack of air movement can promote the growth of these fungi. A thin layer of sand, perlite, or fine sphagnum moss that keeps stems dry at the soil line can also help. After a few weeks, seedling stems toughen and are no longer as susceptible to attack by damping-off fungi. Planting seeds treated with a fungicide are an option for areas where damping-off disease is common. Rotation of susceptible crops using a rotation cycle of four years or longer, can help reduce problems with all soil-borne diseases, including damping-off. Plant when soil temperatures are appropriate; cooler for cool season crops and warmer for warm season crops.
Several biological fungicides have recently come on the market that are used as seed treatments, pre-plant applications, sidedressing, soil drenches, or foliar spraying. Examples include Promot Plus and Mycostop.
If, in spite of all your precautions, you find your garden seedlings toppled over one morning, all you can do is re-plant as soon as possible. Careful site preparation, good cultural care, and proper watering can all help prevent problems with damping-off.
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