Dormant seeding is the common term for over seeding lawns in late fall to early spring while soil temperatures are too cold for grass seed to germinate. In the mid-west that's usually mid-November thru March when soil temperatures are below 50 degrees. Harsh winter weather will not harm dormant grass seeds.
Frost seeding is a type of dormant seeding, overseeding moist soil before freezing weather. The natural freeze and thaw cycle of freezing soils will create small cracks or pockets, perfect for catching and holding grass seed. As the soil dries, the pockets collapse and cover the seed. This same freeze and thaw cycle are also Mother Nature?s natural soil aeration process.
Snow seeding is another type of dormant seeding. It simply requires a light snowfall (up to an inch) that still allows bare spots to be seen. Spread seed by hand on areas that need thickening up. As the snow melts, it brings the seed into good contact with the soil.
Why should you dormant seed your lawn? If you missed the fall over seeding window, dormant seeding helps to eliminate bare spots and thickens turf to fight spring weed pressure. No bare spots will mean no room for ugly summer weeds to invade.
When should you dormant seed your lawn? Dormant seed after the last tree leaves have fallen and been cleaned up. Dormant seed early enough in winter to avoid the muddy conditions from spring thaw and rains. Once you develop a good dormant seeding plan, you will be surprised at the positive results.
What about spring crabgrass? Dormant seeding will conflict with the normal application of Prevent®, spring crabgrass pre-emergent. Most spring crabgrass pre-emergents will kill good grass seed too. For best results in eliminating crabgrass while dormant seeding, follow the steps for spring over seeding using Tupersan®, a seed safe crabgrass pre-emergence.
Uncle's Tip: Using PrimeraFC® seed dressing over the top of grass seed in bare spots will assist in early spring germination. A weed free calcined clay granular seed cover, PrimeraFC®, works like a blanket and absorbs heat from the sun, warming the soil and seed for early germination. Cool season grasses like turf fescues and perennial rye on cold winter soils will germinate sooner than the same grass seed sown in April. Macho Mix fescue seed, Estate Mix bluegrass seed and Stadium Special perennial rye varieties are all cool season blends that will perform well for dormant seeding.