About citrus fruits
Many types of citrus trees adapt to container growing, meaning northern growers can also enjoy freshly harvested fruit. Containers can be moved outdoors in spring, then back inside in fall when temperatures drop into the 40s. Indoors, the plants should be kept in a heated greenhouse or sunny window.
Standard-size orange and grapefruit trees grow 18 to 22 feet tall; dwarf varieties grow 8 to 12 feet tall. Most citrus trees begin to bear at three to six years. Pollination is generally accomplished by insects and sometimes by the wind. Indoor gardeners can hand-pollinate. Most citrus varieties are self-fertile so you need only one tree.
Choosing a site to grow citrus fruits
Citrus will grow in most soils that are moist but well drained. Avoid salty soils. Choose a site protected from wind, with maximum sun exposure.
In the citrus belt, trees can be planted any time of year. Spring is the best time to plant container-grown trees from a nursery. Set standard-size trees 12 to 25 feet apart, set dwarfs 6 to 10 feet apart. (Distance will depend on type and variety.) Set standard-size oranges 20 feet apart, standard-size grapefruit 25 feet apart. Limes and lemons require less space. Plant the trees no deeper than they grew in the nursery container.
Water the entire root area deeply about once a week. Prune any time of the year. When the trees are young, prune overly vigorous growth. Prune mature trees to remove dead, broken, and diseased branches. Give mature trees 1 to 1-1/2 pounds of nitrogen a year. Apply in four portions throughout the year, or just once six to eight weeks before bloom. Citrus trees are susceptible to a number of different disease and insect pests, depending on region. Contact your cooperative extension office for information on managing pests in your area.
How to harvest citrus fruits
Although some varieties ripen their fruit all at once, many others ripen fruit over a period of several months (fall through winter). Taste is the best indicator of ripeness.
Clip off ripe fruit with pruning shears.