Wait until the average date of the last spring frost is long gone. Lawns should be coming out of dormancy and shows signs of fresh green growth. If the lawn has been naturalized with spring bulbs, like daffodils, wait until the leaves of the bulbs have died back before taking care of the lawn. Seeding and fertilizing the lawn early gets it off to a good start.
Remove all debris such as leaves, cones, twigs and small branches from the lawn surface. Rake the lawn to remove dead grass. Remove any rocks. Fill in low areas with top soil.
Inspect the lawn for bare and brown spots. Remove two inches of soil from the bare and brown spots and replace with bagged top soil.
Aerate the compacted lawn in high traffic zones by walking over it with golf shoes that have spikes. Another alternative is poking a screw driver into the soil or renting a machine that will de-thatch and aerate the lawn.
Water with 1 inch of water. Place cups around the lawn to measure the water. Sprinkler heads may need to be adjusted after the winter.
Sprinkle seed over the spots covered with top soil. Place a 1/4 inch of additional top soil over the seeds. Press down lightly. Accelerate the germination of the grass seed by covering the spots with clear plastic--kitchen wrap will work--weighted down with rocks. The plastic traps the heat and moisture.
Spread fertilizer over the lawn per package directions or spray with liquid fertilizer. Avoid the newly planted patches if possible. Water again with 1 inch of water.