Using Leaves as Mulch

Raking up leaves and burning them robs you of valuable, free mulch for the garden.

David Robson is an extension horticulture educator at the University of Illinois. He says leaves are organic matter, so they increase the fertility of the soil as they break down. Leaves also insulate the plants through the winter.

Robson says leaves can be used whole or shredded.

"If you have a big sycamore or an oak tree with large leaves, chances are you're probably going to have to shred them. Some of the leaves will actually mat down instead of break apart, and so by shredding them into smaller pieces, it'll actually help them decompose a little bit faster," says Robson. "If you don't want them to decompose as fast, then a larger piece is really what you're aiming for."

If whole leaves are used, there's the risk of them matting down when wet. This could create a layer that allows no air or water movement underneath. Probably the easiest way to shred leaves is to rake them into a pile and run over them several times with a lawn mower. Then, dump them on whatever places you see fit to mulch.

"If we haven't had a good rain I'll go out there and sprinkle it and I'll even wet down the leaves. It hopefully keeps them from blowing away, and then when we get snow that gives them a little bit more moisture," says Robson. "I will use some of the shredded leaves under some trees and shrubs, or in some containers that I may be leaving outside that I know are freeze-hardy."

If you still have more leaves than you know what to do with, pack them into black plastic bags. Add a little soil, wet them down, and put a few small holes in each bag for air. Toss them into an out-of-the-way place for the winter and in the spring, you'll have leaf compost.

Unfortunately, leaves from nut trees such as walnut and hickory shouldn't be used as mulch because they could be toxic to some plants.