What is dethatching or scarifying? Does my lawn need it?

Dethatching, also known as scarifying, is the process of removing thatch from a lawn that has built up over time. Detatching, or scarifying, removes excess thatch, allowing water and nutrients to penetrate the soil, and encouraging the healthy grass to flourish.

Thatch less than ½-inch thick benefits your lawn, but a thicker thatch layer can harm it. In order to measure your lawn's thatch level, you can use a trowel to dig a small core sample as illustrated here. It's important to only dethatch when needed. Typically, only spreading or creeping grasses need dethatching; bunching grasses do not. Proper timing is crucial for all dethatching projects to ensure the grass is actively growing and can withstand the stress of the procedure. Warm-season grasses are usually dethatched in late spring or early summer (i.e. April-June) while cool-season grasses are usually dethatched in early spring or early fall (i.e. March-May or August-October).