Rake the patches of dead grass and discard the plant debris to expose the surface. If the grass died as a result of pests and disease, treat the problem before reseeding.
Buy commercial lawn soil or mix 1 part topsoil with 1 part peat moss. Spread the blend over the bare surface areas. Make the soil layer 1/4 to 1/2 inch thick.
Select a seed blend of grass species that thrive in your region. In Florida, for instance, plant heat-loving zoysiagrass, Augustinegrass and bahiagrass. In the northern United States, fescue, ryegrass and Kentucky bluegrass are suitable for the cooler climate.
Broadcast the seeds by hand over small sections. To reseed large areas, use a seed spreader set to drop the seeds at the rate recommended on the package label.
Water the soil immediately after sowing the seeds. Maintain the reseeded areas with moist conditions through germination.