The season of the leaf rake and blower is upon us once again—or maybe not, if you garden sustainably.

Rather than removing the leaves from your lawn, you can grind them up in place; a mulching lawn mower will do this if you attack the blanket of leaves before it becomes too thick. Then let the brown confetti filter down through the leaves of grass to serve as what the old-timers used to call a “top-dressing.”

Before the days of chemical fertilizers, top-dressing—spreading a thin layer of organic matter, usually compost or manure, over the turf—was the standard way to feed a lawn. It still works: As the fragments of ground-up leaves decompose, they create a layer of humus around and over the roots of the grass, adding fertility to the soil.

If you maintain your lawn without pesticides and fungicides, the leaf fragments will also provide food for earthworms, which will drag the litter down into the soil, helping to aerate the soil and increase its ability to absorb and retain water.