How to Treat a Sparse, Spotty Lawn

Water your lawn. Your lawn needs to receive about an inch of water to properly aerate the soil. Place a container, such as a bowl, in the grass and draw a mark where an inch occurs. You'll know you've watered the grass with an inch of water when the water hits the inch mark.

Check the soil two days after you've added the inch of water. Waiting two days allows the water to penetrate the soil and become moist, making aerating much easier. If your soil has dried out, spray it down again with water until it becomes moist.

Aerate the soil with an aerator. Sit the aerator on the ground, turn it on and walk back and forth in your yard to punch holes in the soil and remove the grass plugs. Aeration works best when performed in at least two different directions; therefore, push the aerator up and down your lawn, and then from side to side.

Pour the amount of seed you want to spread inside a seeder, immediately after aerating. Adjust the setting on the seeder for the rate the seeds disperse; look at the seed bag's label for instructions, as it varies per type of grass. Walk back and forth in your lawn to spread the seed. Use a slit-seeder in places that are extremely bare. These devices actually create holes in the soil for the seeds to drop into.

Water the seeds until the ground is moist. You'll need to water the seeds every few days or so, depending on the grass and your climate. Mow the grass once it begins to grow. If you don't, the old grass will grow taller than the new grass and block it from getting sunlight.