Overseeding is the process of spreading grass seed over an existing lawn to improve its density and health. This technique is often used to fill in bare spots, enhance color, and promote a thicker turf. It can also help to introduce new grass varieties that are more resistant to pests or drought. The best time for overseeding typically falls in the early fall or spring, depending on the grass type. Before overseeding, it's important to prepare the lawn by mowing it short and aerating the soil. This allows the seeds to make good contact with the soil, increasing the chances of successful germination.