The typical maximum rooting depth of citrus, even when grown in deep, well drained soils, is only 4 to 5 feet, with the main portion of the tree's root system located in the top 2 - 3 feet. Citrus roots can grow much deeper in well drained sandy soils. In a study of citrus trees planted in the deep sandy soils of central Florida, roots of trees on rough lemon rootstock reached a depth of 11 feet, and roots of sour orange trees were found at a depth of 9 feet. Citrus can also survive in very shallow soils, especially when the limiting factors are a high ground water table, or impermeable soil layers. Mature citrus trees grown in areas like the coastal flatwoods of Florida typically have rooting depths of ONLY 18 to 24 inches. - Millet (1,349-)
