Overseeding a lawn is a method of adding grass seed to a lawn to replenish worn-out grass and provide coverage during the winter when warm season grass is dormant. Ryegrass, according to the University of Florida, is the best winter seed to use, as it germinates quickly, grows fast and is adaptable to a variety of conditions. Fescue grass is also acceptable. Overseeding is best practiced 30 days before the first expected frost for the year, recommends Clemson University Extension, so that the weather is warm enough to germinate the seed.
Remove plugs of dirt from the lawn at the end of the summer using a core aerator machine or hand tool to give the seed coverage when spreading and to remove thatch from the lawn that may reduce seed germination, recommends the Clemson University Extension.
Mow the lawn closely a the end of the summer so that the grass is at its lowest recommended height, suggests the University of Florida Extension.
Apply 10 pounds of annual ryegrass seed per 1,000 feet, or 5 to 15 pounds per 1,000 feet of perennial ryegrass, according to Clemson. Sow half the seed going in one direction with the seed spreader, and the other half in a crossing direction. Rake the grass after seeding to break up the soil cores from and cover the grass.
Water the lawn two to three times a day until the seeds germinate, according to Clemson. Lightly water so that the seed does not wash away.
Mow the grass once it is one to two inches long, according to the University of Florida Extension. Continue maintenance as normal throughout the winter so that the lawn does not get too long.