Imagine having sunny orange, bright yellow and luscious green fruit growing in your home, especially during this gray, cold time of year.
While we do not associate citrus plants with our Northeast climate, there are several varieties that can be grown as indoor/outdoor houseplants.
Native to Southeast Asia, citrus plants have been cultivated for over 4,000 years. Their fruit is actually a type of berry with a leathery rind called a hesperidium. They are found in tropical and subtropical regions that offer them warmth, lots of humidity and sandy, slightly acidic soil.
Consistently hot temperatures are needed for citrus fruits to produce sugar, something that our climate cannot offer them. Therefore, sour citrus fruits such as lemon, limes and small orange varieties like Satsuma and Calamondin are among those best suited to growing as houseplants.
In their natural environments, citrus trees can grow to a height of 20 feet, which is certainly not manageable as a houseplant! Thankfully, there are dwarf varieties like tangerine (Satsuma orange), lemon (Ponderosa or Meyer), kumquat (Fortunella species), citron and Calamondin orange. These will reach a more reasonable height of three to five feet.
Plant your citrus in a well-draining pot filled with cactus or citrus soil mix or use regular potting mix amended with perlite. Fertilize with a high-nitrogen fertilizer formulated for acid-loving plants, and only while the plants are actively growing and flowering, generally from April through October.
In winter, place your citrus plant in a sunny south-facing window away from cold drafts and ensure that it receives at least six hours of direct sun per day. Supplement with artificial light if needed. Wipe the leaves periodically to remove dust. Group several houseplants together to create more humidity or run a humidifier near your citrus plant.
As temperatures consistently reach above 50º F in spring, move your citrus plant outdoors gradually, protecting it from direct sun at first. After a few days, place it in full sun and pay attention to its watering needs, which will be more frequent than when it was indoors.
Depending on your citrus variety, you may get flowers only in spring or from spring to autumn. Dwarf citrus varieties are mostly all self-fertile, meaning that you do not need a second plant for pollination to occur.
You do, however, need insects to pollinate the flowers. If your citrus plant is indoors during flowering, you get to play pollinator. Use a clean, dry paintbrush or cotton swab to collect pollen from one flower and rub it on another.
In autumn, acclimate your citrus gradually to move back indoors before the outside temperatures go below 40º.
Don’t be alarmed if your citrus plant sheds some of its baby fruit. Potted plants cannot support that much fruit and will naturally shed the extra. However, fruit drop is also associated with temperature extremes, so take care to avoid those.
Dropped leaves are the plant’s response to overwatering. Flower drop will occur if the soil becomes too dry.
Most importantly, add a little patience to your citrus care routine, as young plants may take years to flower and produce fruit. Lemons and limes can take six to nine months to ripen, and oranges can take up to a year. Those colorful and delicious fruit cheering up your home will be worth it.
by Amy Simone, Extension Master Gardener, UVM
Featured photo: A Calamondin orange tree, a dwarf citrus variety, will bear small, golden-orange fruit so is a good choice to grow indoors as a houseplant. Photo by Amy Simone
