Aerating the Lawn

Typical American lawns grow in compacted soil. The air has been compressed from it by foot traffic and lawn care equipment and its organic matter has long since disappeared. Grass suffers because the roots cannot penetrate this soil and they end up stunted and concentrated near its surface. Aeration, alone or in combination with topdressing to provide organic matter, revitalizes the soil organisms that improve soil texture.
The most direct way to reduce soil compaction is to get air into the soil. To do this, rent a power-driven lawn core aerator or buy a hand lawn aerator tool. These tools remove plugs of turf and deposit them on the grass, leaving holes that admit air down 3 or 4 inches into the soil. If the soil under your turf is very compacted, aerate at least once a year for 2 or 3 years to improve it. Then, if you topdress with organic matter annually, aerating will be necessary only every 4 or 5 years to maintain fertile lawn soil.

Winter Overseeding

Bermudagrass and zoysia grass turn beige and go dormant when cool weather arrives. To have a green winter lawn, overseed these grasses with either perennial or annual ryegrass or a mixture of the two. Do this job in late October or early November:
Set the mower as low as it will go (usually about an inch) and mow, collecting the clippings and debris with a bagging attachment.
Rake the lawn well, leaving live grass stubble and exposed soil. Grass seed must be in contact with the soil to germinate.
Sow ryegrass seed at the recommended amount on the package.
Go over the lawn with an upside down grass rake to make sure the seed is in contact with the soil and not sitting up in the stubble.
Water the new seed every day, twice on sunny days, for 1 to 2 weeks to keep it continuously moist. Do not let it dry out.
Mow when the new grass grows to just a bit over mowing height -- about 2 1/2 inches.