Almost everything, provided they are mulched, watered, and fed well. Clay soil is usually much more of a problem than sandy soil. The only problem unique to sandy soil is nematodes: for unknown reasons they tend to be more of a problem in sand than in loam or clay. I do recommend using slow release sources of nutrients--such as cottonseed meal, alfalfa meal, hoof, horn and hide meal, feather meal, and chicken bone meal-- since more soluble sources will dissappear so quickly with the frequent watering required in sandy soil. Many of these fertilizers will also decay into substances that help to reain water in the soil. Synthetic ureaform or encapsulated fertilizers will also last, but not help the soil. Information on more drought tolerant crops can be found at the Desert Botanical Garden in Phoenix, Arizona (www.dbg.org). Hope this helps!