Loosen the dirt in any bare spots by combing it lightly with a garden rake. For patches bearing yellow or brown grass, remove the plant material by digging down 2 inches with a sturdy shovel. Dig all the way around the affected area, extending the circumference to include up to 6 inches of healthy lawn. Clear any dead or damaged growth and remove any weeds, rocks or debris as you go.
Flush the area with water to remove any contaminants such as pet waste or chemical spills. Then cover the damp soil with a 2-inch layer of commercial potting soil. Incorporate the potting soil into the regular dirt with a garden rake.
Smooth the soil and then scatter an even layer of grass seeds over the planting medium. Be sure to use grass seeds that are well suited to the local climate as these will be more likely to respond quickly to the surrounding conditions. Press the seeds lightly into the surface of the soil with the back of a shovel and then cover the seeds with a ½-inch layer of compost.
Sprinkle water over the compost until the material is evenly moist. Add the water slowly to avoid washing the newly planted seeds away. Check the planting site daily and add water as needed to maintain a moist growing environment. New grass seeds should spring up in four to seven days.
Use sod for an instant fix. Prepare the soil as listed above, but rather than planting seed, cut a piece of sod to fit. Place the sod patch over the bald spot, press it firmly into position and add water. It will only take a few days for the roots to become well established, completely repairing the lawn.