When should you dethatch a lawn?

Lawns should be dethatched when the grass is actively growing, but before the grass is in its strongest growth period. Lawns should also be slightly moist so that the turf is not pulled up by the roots.

Warm-season grasses, such as centipede, zoysia and bermuda, should be dethatched in late spring to early summer in areas that are cooler and receive snow. In warmer regions, dethatching should be done in early spring.

For cool-season grasses, which include fescue, bluegrass and ryegrass, dethatching can be done in early spring or early fall. If done in early fall, it should be done early enough to allow the grass to grow some before any frost arrives.