Orange trees can grow outside in USDA hardiness zones 9 through 11. When temperatures slip below 50°F, the trees will begin to go dormant. The optimal temperature to grow an orange tree hovers ...

For the juiciest fruit, of course, it's best to grow ... an orange tree. Outside, she says, bugs and leaves maintain the organic soil—but that can be hard to replicate from home. "Potted trees ...