From the Garden Helper: "Avocado trees are very versatile in their adaptability to different soils, but they prefer a rich loose sandy loam. They will not survive in locations with poor drainage. . The desirable pH level is generally considered to be between 6 and 7. They will grow in shade and between buildings, but are only productive in full sun. The root system is extensive and will choke out nearby plants, so they should be given plenty of room--up to 20 feet. However two or three trees can be planted in a single large hole to save garden space and enhance pollination. Once established the avocado is a fairly tough tree. Once the tree is a year old, they should be fed four times yearly using a balanced fertilizer. Older trees benefit from feeding with nitrogenous fertilizer applied in late winter and early summer. Yellowed leaves (chlorosis) indicate iron deficiency. This can usually be corrected by a foliar spray of trace elements containing iron. "
