Question: I had started several different vegetable seeds. They started to grow then collapsed to the ground. Any ideas why this happened to all my seeds?
Answer: This is one of the most common reasons new gardeners become frustrated and give up on growing their own seeds. This occurrence is known as dampening off and is most often the result of a fungus known as Pythium. This fungus can affect seeds before they germinate or shortly after they emerge from the soil. A constricted stem just below the soil surface is a sign your seedlings were attacked by a fungus.
These fungi naturally live in all soils, are water-loving organisms and thrive in wet or poorly drained soils. Slow-growing or weak plants are more susceptible to damping-off than vigorous fast-growing seedlings. If the plant can grow roots faster than the fungus can decay them, the plant will survive and be healthy.
The best method of control is to prevent it from occurring in the first place. Use sterile potting mix, clean pots and a fresh bag of potting mix rather than one that was left outside since last fall. If you are using recycled pots cleaning them in a chlorine bleach solution, one part bleach to nine parts water, will help kill the fungus. Place seed trays on clean sterilized benches. If any containers show signs of dampening off, remove them and discard. Wash hands and tools thoroughly so you do not reintroduce the fungi into the other containers.
Make sure there is adequate light and heat during germination. Bottom heat will speed up this process. Also, avoid planting your seeds too deep. Wet conditions also will encourage this fungal disease. Your containers should have drainage holes and plants should not be allowed to sit in standing water for extended periods of time. The water should be lukewarm as cold water slows growth and favors dampening off.
Your soil should be well draining such as soil-less seed starting mix. Sow your seeds thinly to allow for good air circulation. Hav-ing a small fan gently moving the air around your seedlings is beneficial. Hoses and watering heads should be kept off the ground where they could come into contact with infected soil or plant debris. With drier soil, adequate light, good drainage and proper sanitation methods the less likely your seedlings will succumb to dampening off.
Mona Bawgus is a certified master gardener and consumer horticulturist with Rutgers Cooperative Extension of Atlantic County.
Write to her c/o Rutgers Cooperative Extension, 6260 Old Harding Highway, Mays Landing, NJ 08330. Email: