dartagnanpluck,

I have been looking into this also, and the best information I find is 10:1 ratio (10 parts water to 1 part peroxide). I am guessing that a spritz or two each week would do the trick.

If you go to the PA gardening forum, we are planning a plant trade in the NEPA area for spring, I hosted last year, and will probably do so this year also. It was fun, but it was also the first weekend of the rains we had that caused all the flooding in June...we got wet, but had fun.

Gerry

I use regular hydrogen peroxide 3% undiluted on the soil, prior to putting seeds or on top of seeds/ not germinated ones/. I also use clean pots and sterilize them with soil in microwave.
Small fan near your trays will go a long way toward fight with damp off.