Mulching is one of the simplest and most beneficial practices you can use in the garden. Mulch is simply a protective layer of a material that is spread on top of the soil. Mulches can either be organic—such as grass clippings, straw, bark chips, and similar materials—or inorganic—such as stones, brick chips, and plastic. Both organic and inorganic mulches have numerous benefits.
protects the soil from erosion
reduces compaction from the impact of heavy rains
conserves moisture, reducing the need for frequent waterings
maintains a more even soil temperature
prevents weed growth
keeps fruits and vegetables clean
keeps feet clean, allowing access to garden even when damp
provides a "finished" look to the garden
Organic mulches also improve the condition of the soil. As these mulches slowly decompose, they provide organic matter which helps keep the soil loose. This improves root growth, increases the infiltration of water, and also improves the water-holding capacity of the soil. Organic matter is a source of plant nutrients and provides an ideal environment for earthworms and other beneficial soil organisms.
While inorganic mulches have their place in certain landscapes, they lack the soil improving properties of organic mulches. Inorganic mulches, because of their permanence, may be difficult to remove if you decide to change your garden plans at a later date. Therefore, this tip sheet is limited to the use of organic mulches.
Mulch materials You can find mulch materials in your own yard! Lawn clippings make excellent mulch. While not particularly attractive for a flower bed, they work wonderfully in the vegetable garden. The fine texture allows them to be spread easily even around small plants. However, grass clippings are becoming scarce because of the increased popularity of mulching lawnmowers that provide many of the same benefits of mulching to lawns. Newspaper, as a mulch, works especially well to control weeds. Leaves are another readily available material to use as mulch. Leaf mold, or the decomposed remains of leaves, gives the forest floor its absorbent spongy structure. Compost makes a wonderful mulch if you have a large supply. Compost not only improves the soil structure but provides an excellent source of plant nutrients.
Bark chips and composted bark mulch are available at garden centers. These make a neat finish to the garden bed and will eventually improve the condition of the soil. These may last for one to three years or more depending on the size of the chips or how well composed the bark mulch is. Smaller chips tend to be easier to spread, especially around small plants. Depending on where you live, numerous other materials make excellent mulches. Hay and straw work well in the vegetable garden, although they may harbor weed seeds. Seaweed mulch, ground corn cobs, and pine needles can also be used. Pine needles tend to increase the acidity of the soil so they work best around acid-loving plants such as rhododendrons and blueberries.