Doug Before you start again Soak your seed starting trays in some water and houshold bleach 5 to 10 min, then let dry completely. Personal recommend, Use sterile seed starting medium. Use a small fan blowing air across the soil surface. Don't cover the surface of the soil with anything. Allow the soil surface to dry for 12 to 24 hours between waterings. This will knock down most of it. ROR (aka Rots of ruck) L.B.