Lawn aeration improves the soil by removing small diameter soil plugs from the ground. The plugs are then deposited back onto the top of the soil. The small holes in the lawn improve drainage and aid in breaking down the thatch material left behind by decaying grass and twigs. Mechanical aerators are found at local equipment-rental shops. There are also spike type aerators, but these will compact the soil more than the plug removal type.
Broadcast the grass seed onto bare areas of the lawn. Follow the recommended amounts on the seed package labeling as various types of grass will have different seeding rates.
Spread a layer of compost material over the lawn 1/4 to 1/2 inch thick. The new compost addition will cover the new grass seed. The seed and compost addition will be incorporated into the soil by the use of the mechanical aerator.
Aerate the lawn using the mechanical aerator. Overlap each pass so the lawn is filled with the small plug deposits from the machine. It is better to overlap areas than to leave any portion of the lawn not aerated.
Water the freshly aerated lawn and the new seed with the garden hose and sprinkler attachment. Add approximately 1 to 2 inches of water to the lawn each week. Maintain the watering amounts and schedule throughout the growing season, unless local rainfall amounts exceed the requirements.
Mow the lawn on a weekly basis to keep old growth down. Set the mower height between 2 and 2 1/2 inches. This will allow more sunlight to the new grass seed.