Mulches cover the soil and reduce evaporation from planted areas. They cool the soil beneath and also help to inhibit weed growth and erosion. There are organic mulches and inorganic mulches. The most popular organic mulches in our area are bark chips and wood grindings. These are often used in planting beds and other small areas. The natural drop of leaves, flowers and fruit can also be left on the ground as mulch. Decomposed granite and crushed rock are two of the most popular inorganic mulches, especially in the Arizona climate.