Prepare the soil in the patch by removing weeds and dead grass. If the patch contains a thick layer of debris, use a thatch rake to clear the area. Locate any places that may collect excess water. Level these spots with existing topsoil.
Sow the grass seed over the patch. Scatter the seeds by hand at a rate of approximately 16 per square inch. Spread the seeds evenly by raking the area until the surface is smooth. Apply a starter fertilizer to aid in germination.
Keep the seeds moist by watering regularly until the roots develop. Apply a light coating of water once a day until the new grass reaches a height of 2 inches.