I use H2O2 for the first few waterings of my newly sown seedlings.
After they pop, I add 1 tsp. to a gallon of water (always tepid), and gently top water with a turkey baster, applying the water around the base of the seedlings, so they are in contact with the H2O2. To date, I haven't lost a single seedling to damping off! After 1-3 top waterings like this, I begin bottom watering in the drip tray, and continue with the H2O2 for about the next two waterings. So, that makes a total of 5 applications of the H2O2. I also use the turkey baster to suck out the water from the drip tray after about 15-20 minutes, so the seedlings aren't constantly sitting in water. Too wet soil will definitely contribute to damping off!
Then, I move on to bottom watering with plan water, and, after potting up, when the seedlings are much further down the line, I begin adding a scant 1/2 tsp. of MG Water Soluble Plant fertilizer to the gallon of water.
I started 208 tomato seeds and 65 bell pepper seeds this past January, and didn't lose a single one to damping off.
Hugs!
Linda
