What is dormant seeding?
This is a process where seed is sown during the winter months of November to March. The seed will remain in a dormant state until the ground warms up and soil moisture is adequate to promote germination. The key to dormant seeding is good seed-soil contact. A good way to create places for the seed to germinate is to core aerate the lawn prior to seeding. You can rent a core aeration machine if you have a vehicle large enough to transport it and the muscle strength to handle it. Most people hire a lawn service to do the work for them. The lawn has to be moist for good penetration of the coring tines and, of course, the ground cannot be frozen.
The seed is generally spread with a rotary-type spreader that will evenly distribute the seed across the lawn. Depending upon the seed you are using spread about three to six pounds of seed per one thousand square feet. For example, bluegrass seed contains about 1.5 million seeds per pound whereas Turf Type Tall Fescue contains about 250,000 seeds per pound. A little bit of bluegrass goes a long way.
It is very important that you do not apply pre-emergent crabgrass preventer during the spring. These products create a barrier that kills newly germinating crabgrass seeds. It will also kill the new grass seed that was put down. You may have to live with some crabgrass for a year, but if you water and mow high you can keep its population in check.