HelpfulGardener.com

it's damping-off time again, that dreaded fungal disease that topples seedlings at the soil line. Solutions presented here and other places include watering with chamomille tea, powdering with cinnamon, even using hydrogen peroxide. One very popular book on orgenic gardening recommends with a straight face that you sterilize your containers and use sterilized seed-starting mix, then water with compost tea (bye-bye sterility).

The fact is, damp, cool conditions awaken most of the fungii that cause damping-off, so bottom water and keep the soil surface reasonably dry. An oscillating fan set on low not only keeps things nicely dry, but activates the hormone that makes seedlings more stocky and sturdy (it mimics breezes in the outdoors.).

As to the potting mix, we’ve included compost in ours for years, top-watered tens of thousands of seedlings in our greenhouses, allowed the soil to dry before waterings, and virtually never lost a plant to damping-off.

If you have a greenhouse that makes things easier... more fresh air and more air circulation. For those of us starting seeds in our basements, it's a little trickier. If you are starting seeds, it's a fine line. Letting the soil dry out kills the fungus, but you can't let seeds dry out or tiny baby seedlings either. That's why I use the chamomile and a tiny bit of cinnamon in the water I water with. Before I did that, I would lose a few plants to damping off and I had a lot of fungus gnats. Since I've been doing that all the time (I.e. preventatively, not after there's a problem), I have had zero of either.

I have less problems with damping off when I keep my light brighter. It's when the plants get neglected and move away from the growlights that I may have damping off.