Plant your orange tree in an area with full sunlight and good soil drainage. If you are planting a new tree, dig one part compost into the soil for every four parts of soil. If you have an existing tree, spread a 2 to 3 inch layer of organic compost on the soil as a mulch to give the tree continuous nutrients.
Water your orange tree when the soil becomes dry to a depth of 2 inches. Drip irrigation systems work well. If you haven't set up a drip system, simply run your garden hose at a slow drip near the trunk for 30 minutes.
Fertilize your tree three or four times during its active growing season, beginning in spring and continuing at evenly spaced intervals until late summer. Use a commercial plant food designed for citrus or organic alternatives such as fish emulsion or worm castings.
Cover your tree with a tarp or blanket on nights when frost is likely to occur. Another method of protecting your tree is to string Christmas lights through it and keep them on all night during cold weather.
Maintain your tree's health by keeping its growing area free of weeds, which can compete for nutrients. Also control all insect pests, such as aphids, by spraying the tree with insecticidal soap when you notice an infestation.