With preparation, overseeding reduces weeds, thickens lawn turf and fills in bare areas. Overseed lawns during the months of September and October. Use the same amount of grass seed as required for seeding a new lawn, and use the same type of seed that is present in the existing lawn. Use overseeding to thicken your lawn instead of hiring a landscaper or lawn specialist to do the work.
Set the lawn mower blades to a 1-inch cut. Start at the corner of the lawn and mow back and forth in straight rows.
Rake the lawn with a wide-tine rake to remove small twigs, rocks and other debris.
Rent a lawn aerator, if you do not own one. Start at the corner of the lawn and roll the aerator back and forth in straight rows over the entire lawn surface.
Water the lawn with 1 inch of water. Allow the water to penetrate soil for 30 minutes.
Fill a seed spreader with grass seed that is identical to the seed currently in the lawn. Follow the recommendations on the bag to determine spread amount.
Water the lawn with 1 inch of water once again. Repeat watering every other day for 14 consecutive days.