Growing orange trees in the desert might seem to be a hopeless task. When you think of oranges you probably think of lush green California or tropical Florida. The desert around Phoenix, Arizona, has major citrus groves that include oranges. The mild winter temperatures are perfect for oranges. Almost all that's needed to add is water.
Select valencia, navel, Arizona sweets and Mandarin orange varieties that grow well in the desert.
Dig a hole that is 3 feet deep by 3 feet wide for a 15-gallon size tree. Plant larger trees in holes at least 2 feet bigger than the size of the tree's container.
Mix half of the removed soil with equal amounts of bagged topsoil, compost and organic matter. Backfill the hole with the mixed soil and amendments high enough that the depth the tree is planted at the same depth it was in the pot. Water enough to settle the soil. Add more soil, if necessary, to attain the required height in the soil.
Score the sides of the root ball with a knife before planting if the roots are compacted. Plant the tree and cover the top of the mixed soil with a 4-inch layer of garden soil to prevent the orange tree from drying out. Mound the soil around the tree to form a well that's 3 feet in diameter and about 6 inches high.
Water the tree once a week for the first month after planting by letting the well fill up with water. Water deeply every few weeks after that, more often in hot summer months and less often in cooler winter months.
Fertilize with a citrus fertilizer twice a year in February and August. Water well before and after fertilizing. Fertilize more if leaves are turning yellow.
Protect the orange tree from freezing and cold temperatures by covering it with a blanket or stringing it with ornamental lights.