Orange trees come to fruit bearing maturity slowly and often need to be transplanted several times during their establishment period. Orange trees should be transplanted in the spring or in the fall when the supporting climate conditions are mild and no undue strain is placed on the trees. Whether you are stepping up the tree into a larger pot or transplanting into the ground, maintaining moisture in the root ball, minimizing root disruption and providing rich soil are the keys to successful transplantation.
Time of Year
The best time of year to transplant orange trees is the time they will be under the least amount of environmental stress. For most climates, this translates into spring transplanting and early fall transplanting, skipping over the heat and drying conditions present during the summer and the cooler conditions in winter even in temperate climates.
Maintaing a Moist and Intact Rootball
Two keys to successful transplanting is carefully excavating as much of the root ball as possible with the soil attached and keeping that entire unit moist. If the time between excavation and replanting is longer than a few minutes or hours, wrapping the root ball in burlap and wetting it down thoroughly is the best option to ensure a safe waiting period.
Orange trees need to be transplanted into rich, well-drained humus that is well tilled and loose so that the roots can easily penetrate the new soil. The prepared soil area should be at least twice the diameter and half again as deep at the untrimmed root ball. If your tree is nearing maturity, select a location that can sustain the tree at its full size of approximately 10 feet tall and 8 feet in width. Transplanting mature trees is not recommended because it could cause trauma that would disrupt the fruiting cycle and root system health. Apply a slow release fertilizer in the moist soil before planting, water the newly transplanted tree well and then on a consistent basis afterward.