How Mulches Save You Work and Benefit Your Soil

Any material applied to the surface of the soil as a barrier, to retain moisture in the soil, prevent weed growth, etc., is a mulch. Plastics, roofing paper or insulation fiber will serve. However, natural organic materials are the things most often used; they decompose in time, contributing to soil improvement.

A good mulch should let rain seep through, but be tight and thick enough to smother sprouting weeds. Usually it is applied four inches thick in shrub, vegetable or flower beds but it soon packs down to only a few inches. More can be added if bare spots develop or if weeds start coming through. New lawns require only a loose fraction of an inch of a fine-textured mulch to allow the grass plants to push their way through.
Organic mulches decay toward their bottom where they meet moist soil. This benefits the soil through the release of nutrients and materials that help make the soil surface crumbly and receptive to moisture. The mulch also helps by insulating the soil against extreme temperature changes and rapid drying.


One of the handiest sources of mulching material around the home is lawn clippings. Spread them no more than an inch thick at a time until they dry. Finished compost is excellent, if you have enough, but it is used better if worked into your soil. You can purchase any number of materials at the garden store, including peat, rice hulls, pulverized or ground bark, wood chips, etc.
In some localities tree trimming companies chip up trimmings which you can obtain free for the hauling. They make an acceptable mulch. Sawdust tends to pack a little tight, so rain and air cannot penetrate, but after it has partially decayed it is satisfactory. Hay, straw or similar local materials are useful where their appearance is not considered unsightly and if weed seeds are not being imported.

Sometimes much of a plant's root system grows just under the mulch, as for example the azalea's. Then one has to be careful not to disrupt the mulch by too much cultivation. In the vegetable and flower garden, the mulch functions during the annual growth period; after that, it can be tilled into the soil, or left on permanently and added to as needed.