How To Prevent and Stop Damping Off
You think you're doing well with your young seedlings and then they start falling over (the tops are often still green when they fall).
What is happening is that the damping off fungus has attacked the stem right above the soil line.
Causes of Damping Off
Overcrowded seedlings reduce air circulation and allow damp conditions (perfect for fungus to establish) at the base of the seedlings. You've likely sown the seeds too thickly
Poor air circulation - if the seedlings are crowded, damping off is easily established. For example, do you cover your seedlings with a clear plastic cover reducing air flow).
In the greenhouses, I had air fans blowing air over top of seedling trays to keep the air moving. In your home, put a fan blowing air across the top of the seedlings so the air jet is approximately 3 feet above the seedlings. This will move air but not blow directly onto the seedlings (and dry them out quickly). Remember once the seeds germinate, you don't have to cover the seedlings.
Cold temperatures. If you don't keep those seedling trays warm, you'll have more trouble with damping off. Start seedlings on seedling or ensure the soil temperatures are at least 70F (remember soil temperatures are 10 degrees less than air temperatures). Reduce to room temperatures when the seedlings have 4 true leaves and get them off the mats at that time.
Combination of the above.
Stopping Damping Off
The obvious solution is to thin out the seedlings, heat the seedling tray and increase ventilation. Prevention is certainly the easiest way to solve this problem.
But if you have it- what to do about it?
The first is to take care of the above. Thin out the seedlings by removing all dead and dying (you'll see a black sunken area on the stem) seedlings. Remove plastic covers to increase the air flow. Make sure the growing temperatures are in the 65F range (plus or minus a degree or two).
Water with lukewarm water.
The Simplest Solution
The simplest spray to stop this problem in its tracks is to take several cloves of garlic and mash them up into an inch of water in a saucepan. Simmer to dissolve the oil. Allow the water to cool to lukewarm (so you can comfortably put your hand in the water) but not cold. And pour this mixture over the seedlings - flooding the seedling tray with it.
Garlic is a natural bacteria and fungicide and it will stop the damping off complex of pathogens in its tracks. Simple, cheap and environmentally effective.
But do solve the causes of the problem first.
Online Shopping for Things Mentioned in This Article
You can find a rather large selection of annual flower and vegetable seeds online here
Artificial soil and similar
Heat mat for seedling success
