This broad definition could include organic materials such as wood chips, pine needles, straw, peat moss, corncobs and lawn clippings. Inorganic mulches would include river rock, ground tires, volcanic rock and synthetic fabrics. Generally organic mulches are preferred for plant growth because of their ability to improve soil structure and provide a more natural environment for good root growth and, therefore, good top growth of the plant. Mulches can also increase water penetration into the soil. Maintaining a uniform soil temperature by insulating the soil.
Mulches keep the soil warmer during cool weather and cooler during warm weather.
Minimizing soil erosion and compaction from heavy rains, heavy lawn mowers, heavy people and heavy thoughts. Improving soil structure through the decomposition of organic mulches. This is particularly important in heavy soil types. Mulches keep clay soil from cracking after rains. Mulches encourage worm activity and other beneficial life in the soil.