A layer of mulch retains soil moisture and controls weeds, and organic mulches--such as dry leaves, peat moss or pine needles--add vital nutrients to the soil. Making the effort early in the season to apply mulch to your vegetable garden will save you time and energy later on, and will increase your yield. Mulch should be applied after your seeds have germinated, and wait until the soil is thoroughly warm to mulch around heat-loving plants like tomatoes, pepper, eggplant or melons. Most mulches should be applied to a depth of 2 to 6 inches, depending on the density of material.
Compost is recommended by agriculture extension office across the country, and is one of the best mulches you can apply to your vegetable garden. Compost allows more water to filter into the earth than other mulches, does not alter the pH of your soil, and increases soil fertility. Top an application of compost with a thin layer of leaves, straw or other organic mulch to increase weed control. You can make your own compost by allowing kitchen waste and yard trimming to decompose in a bin or pile, or you can purchase compost in 50 pounds bags at any garden center.
Newspaper and Cardboard
Recycle old newspaper and cardboard in your own back yard by using them as mulch in the vegetable garden. Lay a single layer or corrugated cardboard or 4 to 6 sheets of newspaper between rows or around large plants, and top with a light layer of leaves, grass clippings, straw, or some other organic mulch to hold it in place. Newspaper and cardboard will decompose over a single growing season, and whatever is left can be tilled under in the spring. Avoid using glossy or colored papers.
Leaves, Pine Needles and Grass Clipping
These mulches have the advantage of being free and easily attainable from your own yard or your neighbor's yard. However, leaves and grass clippings may clump together in a thick mat, and pine needles may alter the pH of your soil. Use pine needles around plants that thrive in acidic soil, such as blueberries or potatoes, and mix leaves or grass with a fluffy material like straw, or use them on top of a layer of newspaper or compost.
Straw and Hay
Straw and hay are lightweight and easy to work with, and they add a rustic, rural charm to even the most urban backyard vegetable garden. Try to use straw that has been sterilized, otherwise it may contain weed seeds, which would defeat the purpose of mulching. You may need more than one application of straw or hay over a growing season. Straw is readily available at garden centers, and hay may be purchased directly from farmers.
Wood Chips and Shredded Bark
These mulches are the most attractive---and also the most expensive. They decompose slowly and may be reused over several growing seasons, simply rake them off and reapply if you need to till the soil. In the vegetable garden, their best use is on permanent pathways or in raised beds.
Plastic Sheets and Landscaping Fabric
Inorganic mulches like plastic or landscaping fabric add no nutrients to your soil, and plastic especially makes it difficult for water or fertilizers to reach the roots of your vegetables. Landscaping fabric and plastic sheets may be reused year after year. According to the Virginia Cooperative Extension Office, red colored plastic may increase tomato yields.