How to Re-Seed a Sparse Lawn

Apply a liquid lawn herbicide in late August. Wait three to four weeks before proceeding to the reseeding process, since herbicides can interfere with seed germination.

Fill a seed spreader with all-purpose lawn fertilizer. Walk the spreader over the sparse lawn to spread the fertilizer to all parts of the yard. Apply 10 lbs. of fertilizer per 1,000 square feet of lawn. Use the garden hose to water the fertilizer into the lawn. Allow the grass to dry before proceeding.

Rake the lawn with a stiff-toothed garden rake to remove the underlying thatch. Thatch is the collection of dead and dried grass clippings that resides on top of the soil, hidden from view under the living grass.

Place good-quality grass seed into the freezer for 24 hours to help aid the rate of seed germination. Remove the grass seed from the freezer right before you begin the reseeding process.

Rent a lawn slit seeder from a local lawn supply store. Fill the slit seeder with the good quality grass seed. Roll the slit seeder over the entire lawn, or over isolated sparse areas. Walk the slit seeder in a horizontal direction for the first pass. Fill the slit seeder with grass seed as soon as it empties and walk the seeder in a vertical direction for the final pass.

Spray the reseeded lawn with a garden hose until moist. Cover the reseeded lawn with straw, labeled weed-free. Continue to water the reseeded lawn two to three times each day to maintain even moisture while the new grass grows 1 inch tall.

Mow the top ¼ inch of the new grass, with a lawn mower, as it reaches 2 ¼ inches tall. Continue to mow the new grass down to a height of 2 inches to speed the new grass's maturity.

Allow the new grass to grow 3 inches tall after the third or fourth mowing. Apply 4 lbs. of lawn fertilizer, using the seed spreader, for every 1,000 square feet of lawn. Water the fertilizer into the lawn to avoid burning the new grass.