When starting seeds indoors, you do not have to worry about the weather, insects, or the myriad of plant diseases and fungi that can affect your outdoor vegetables, trees, or flowers.
There is, however, one disease you must be concerned with when starting seedlings in the house or greenhouse and directly in the garden, called damping-off, which quickly can turn the initial joy of seeing your young seedlings poke through the soil and start to grow into a complete crop failure almost overnight.