Damping Off

I had a flat of hollyhocks to germinate beautifully then keel over and die. They probably had a fungus on the seeds as they were self harvested. Now I have a bunch of new seedlings and don’t want them to die. So I put a fan in the greenhouse, sprayed the foliage with a weak solution os peroxide diluted with water, and intend to sift cinnamon onto the soil as that is supposed to be a natural fungicide. So far the seedlings have survived my tlc.