Dethatching is the process of removing thatch from lawns, which is a layer of debris, dead grass, and other organic matter that lies between grass blades and the soils surface. Thatch can stifle the growth and health of grass or turf, and removing it helps the grass by encouraging it to thicken up and become stronger and less susceptible to disease. Dethatching is usually carried out by machines of a professional standard which are normally powered by gasoline engines, but smaller, less rigorous electric machines are also available for the domestic market. Dethatching can be accomplished with a simple rake, making it an easy DIY project.

Benefits of dethatching include giving grass roots access to nutrients, water, and air, improving soil health and nutrient density, exposing lower grass shoots to more sunlight, and improving grass health and curb appeal. The best time to dethatch depends on grass variety and location but is optimal when the lawn is actively growing and has time to recover. Late summer or early fall before the grass goes dormant are good times to dethatch cool-season grasses, such as Kentucky bluegrass, while late spring is a good time to dethatch warm-season grasses, such as Bermudagrass or Zoysia grass.

Some tips to prevent dethatching in the future include avoiding over-fertilizing, over-watering, and over-mowing, as well as aerating the lawn regularly.