Now that we’ve discussed the Soil v. Compost question, we’ll move on to Mulch. First, mulch is one of the best summer practices you can do in your garden. Second, mulch is not really soil or compost, so you don’t want to use it as a planting medium. Mulching a desert vegetable or flower garden should be done before the high summer heat becomes constant.
Mulch is a protective layer of material that you spread on top of your soil several inches thick. Mulching is a simple and highly effective way to help your garden, especially as summer nears. It helps soil retain moisture, stay cool and it inhibits weed growth; soil temperature and water retention are very important for desert gardeners.
Mulches can be organic – think bark chips, straw, grass clippings, pine needles, dry leaves, shredded newspaper, even compost. Or they can be inorganic, such as decomposed granite or other small stone. Inorganic mulch is often used to give gardens a tidy look, but remember they can be a lot of work to move if your garden plans change.
As organic mulch slowly decomposes, it adds organic matter to the soil which helps keep it loose, improving root growth and increasing water retention. Organic matter is a source of plant nutrients and provides an ideal environment for earthworms and other beneficial soil organisms.
If you live in an area where hard freezes are common in the winter, you might want to read more about winter mulching in the USDA’s Backyard Conservation Tip Sheet on Mulching.