Citrus trees make a pretty and fragrant houseplant for a sunny window. If the flowers are pollinated, you will also be able to harvest some fruit in the fall or winter, with a few varieties producing fruit year-round. A citrus tree can live inside all year, or you may wish to summer it outside (and let the bees do the work of pollinating the flowers.) While most varieties of citrus grow into very large plants, keeping them in a container tends to “dwarf” the plant, making them suitable for use indoors.
Sunrooms or large south-facing windows are great spots to grow a citrus tree. It is best, however,
to keep the plant away from a source of hot, dry air. Water thoroughly with day-old, room temperature water when the surface soil is dry to the touch (larger containers may need to dry down an inch or two) until some water appears at the bottom drainage holes. Discard any drainage water that is not taken up by the root ball within 15 minutes or so.
In spring and summer, apply a general purpose fertilizer every three to four weeks. Some growers
recommend an occasional application of Epsom salts (1 tablespoon per 2 gallons of water.) Occasionally leach the soil by running water slowly through the root ball for several minutes—this will
remove any soluble salts that may have accumulated from tap water or fertilizers.
Prune a citrus tree after fruiting to maintain an attractive shape or control the overall size. When
it’s time to repot, always use a container with drainage holes, selecting one that is only one or two inches larger in diameter. Over-potting can cause the plant to stay too wet or it may delay fruiting. To
pollinate a citrus, use a small artist’s brush to spread pollen from one ripe flower to another. Tiny fruits will follow the faded blossoms, although they take a long time to mature. It is normal for a citrus tree to drop some of its fruits as they begin to enlarge.
Everbearing varieties of citrus are best for growing indoors, since they can flower and fruit any time of year. Good choices include the dwarf ornamental Calamondin orange, Meyer lemon, Eureka
lemon, Key lime, Limequat, and Persian lime. If you plant a seed from an orange or a grapefruit, you can grow a large, leafy tree; however, it usually takes years to produce flowers and fruit. Commercial citrus growers use specific root stocks for traits such as higher yields, disease resistance, and