Wood chips, dry lawn clippings, old straw and pine needles all work to keep the dirt from drying out. Sawdust is not recommended because it removes nitrogen, an important nutrient. Microclimates Some desert gardens use microclimates to benefit the plants. North facing walls provide cool shaded areas. Roofs, sidewalks and streets create areas of high water runoff for collection.
Cool air flows into valleys.
Be aware of walls and paving which add heat and channel winds. The microclimate includes variables such as sunlight, temperature, exposure, humidity and wind. Big differences can be found in microclimates among neighboring houses. Color influences microclimates, as dark rocks or walls retain heat, and white reflects it. Cactus Even cactus gardeners face a challenge in the Chihuahuan desert.