What Is Good Mulch?

Mulch is any material that is placed on the ground around plants. Mulch saves soil moisture, reduces weed growth and suppresses soil-borne diseases. Mulches may contribute to the organic material in the soil, which in turn makes the plants more productive. Good mulches come in a wide variety of materials, either organic or non-organic.

Leaves are a free mulch provided by nature. A 2- to 3-inch layer of shredded leaves decomposes within a few months and must be renewed. Watch the mulch carefully to ensure it is not matting down and creating a condition where the water runs off instead of soaking into the ground. Shredded leaves also provide a fertile area for weed seeds to grow. Use oak and beech leaves if you have acid-loving herbs such as anise, chamomile, fennel, tarragon and thyme.

Dark-colored and attractive, pine bark bought in bags provides effective weed-control. They are as beneficial around a site that easily floods since they will float away. Pine needles also come free, like leaves. Water penetrates to the ground easier than with leaves but excessive use of needles as mulch can affect the soil's pH balance. Because of their waxy coating they do not quickly decompose. Use pine needles for acid-loving herbs, flowers and shrubs.

Hardwood mulch is a the standard mulch because of its many benefits. It is attractive, effective at suppressing weeds, and unlike other wood products, will not easily wash away in the rain. Shredded or chipped hardwood mulch comes from a variety of trees. Many people believe that wood mulch draws too much nitrogen from the ground and hurts plants growth, but as long as the mulch is on top of the ground it does not affect nitrogen balance.

Inorganic mulches such as small stones, river rocks, and gravel are more suited for a permanent setting such as foundations and walkways. Specially made black plastic or landscape cloth mulch works under the soil to suppress weeds and retain water. The material is porous, allowing the necessary water and fertilizers to slip through. Plastic tears easily and is not good where many people walk. Shredded rubber auto tires are sometimes used where there is significant foot traffic.