dethatch

Etymology

de- + thatch

verb

1. (transitive) To abrade the surface of a lawn or turf in order to remove dead grass.
   The services available vary widely, from basic tasks like mowing and edging walkways and flower beds to more involved work like trimming shrubs and bushes, applying fertilizer and pesticides, and dethatching, which removes layers of dead grass. June 12, 2008, Jay Romano, “Grass, Simplified: Hire Someone”, in New York Times