Dormant seeding is the process of applying grass seed to lawn areas in late fall/early winter or after the ground has frozen. The seed does not germinate because of the cold temperatures. It sits on the frozen surface protected by snow cover during the winter months. In the early spring, due to the soil movement as the ground thaws, the grass seed works its way into the soil and is able to establish good soil contact.
Problems can occur if seed sits in areas prone to puddling. In those areas, if trapped in frozen patches, the seed can be killed. Seed also has the potential to rot if excessive springtime water cannot drain properly. The main advantage of dormant seeding is to get a "jump" on the spring season, as early spring soils can be wet and unworkable which can put a project behind schedule