Orange trees, as with any other fruit tree, should be planted or transplanted during a time of year and season likely to cause a minimum of stress to the roots, foliage and blooms. As orange trees thrive in temperate to subtropical climates, this often translates into early spring or early fall, avoiding the heat of summer and the relatively cold temperatures of winter.
Plant or transplant orange trees in the early- to mid-spring before bloom, after all threat of frost has passed and daily temperatures are above 50 degrees F. Choose rich, well-drained soil and a sunny location, preferably with a southern exposure. Whether directly planted in the ground or in a container, choose an area with protection from frosts and cold winds, such as the southern exposure of a building or other protected and mild micro-climate. Water in the new tree well and do not allow the soil to dry out, but do not water so much that the roots are drowning in standing water. Wait several weeks to two months to allow the roots to establish themselves before feeding with a citrus fertilizer.
Orange trees should be planted or transplanted in the early fall after the hottest heat of summer has passed and the temperatures are still consistently above 50 degrees F during the day. As with spring planting, water in the tree well, maintain moist soil at the roots and fertilize with a high-quality citrus food a few weeks after planting.