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How To Grow Star Fruit Indoors

How to Grow Sunny Star Fruit Indoors Featured Image

Looking for an easy-to-grow fruit that will bring light and sparkle to your gardening life during the darkest months of the year? Tasty, tropical star fruits (Averrhoa carambola) may be the answer, even if you live in a cold-winter climate. Dwarf trees have made indoor growing possible.

Angular star fruits are succulent and taste much like tangy grapes. At home in the tropics of Southeast Asia, hanging from 20- to 30-foot tall trees, star fruits don’t look very celestial. Yellow-orange in color and 3 to 4 inches long, each sports a waxy skin with five prominent greenish ridges. When the fruits are cut crosswise, those ridges morph into the five points of a star, giving rise to the common name.

A Century in North America

Indoor star fruit tree

Though exotic in appearance, star fruits, also sometimes known as carambola, are not newcomers to the North American scene. The trees first arrived in Florida about 100 years ago and have been grown commercially and in Florida, California, and Hawaii ever since. Early star fruit varieties were smaller and very tart, but breeding improvements have led to the larger, sweeter fruits, that are available in supermarkets today.

Versatile Star Fruit

Chopped star fruit
Crisp, sweet star fruit shows off its starry looks when cut.

All parts of the fruit, including the rind, flesh, and seeds, are edible and provide vitamins A and C, plus minerals. Eaten out of hand or used in salads or desserts, star fruit is both tasty and decorative. Most people can enjoy them regularly, but they are high in oxalic acid, which can cause kidney problems for those with related illnesses, so consult health care providers before eating lots of them.

Growing Star Fruit Indoors

Orange star fruit
Some star fruit varieties have orange mature fruits while others are more yellow or yellowish-green.

If you live in a cold-winter climate, you can enjoy homegrown star fruit if you pick a dwarf variety, like ‘Maher Dwarf’, which has sweet, crunchy fruit, or ‘Dwarf Hawaiian’, which has super sweet fruit, in large containers—at least during the cold weather months. Both varieties bear fruit when trees are just a few feet high, and they are self-fertile, so their clusters of pink flowers don’t require pollination.

To flourish indoors, potted star fruits need well-drained, loamy soil (Fafard® Natural & Organic Potting Mix) with a slightly acid pH (5.5-6.5) and regular fertilizer for acid-loving fruit trees. Provide them with lots of sunshine and enough water to keep the pots just moist. The trees perform best when temperatures are above 60 degrees Fahrenheit and the air is moderately humid.

Dwarf plants are best for pot culture because they are bred to stay compact. Depending on your finances and level of patience, you can begin your star fruit journey with a starter specimen in a 6-inch pot or choose a mature 3- to 4-foot tree. Buying a larger specimen is a faster route to fruit, while smaller plants take a while to produce but are the least expensive.

Either way, give your new potted star fruit a good start by trading its nursery pot for a slightly larger one and filling it with our high-quality, natural and organic potting mix. If the plant will travel between outdoor and indoor locations, opt for a relatively lightweight pot or use a pot platform with casters that can be wheeled back and forth as the seasons change.

Growing Star Fruit Outdoors

Outdoor star fruit
Pick star fruits when they are fully colored. If you are not sure, pick one and test it for sweetness.

As tropical denizens, star fruit trees love warmth. If possible, let them spend the late spring, summer, and early fall soaking up sunshine outside. A protected location shielded from wind will help keep trees healthy and happy. If you choose a starter specimen in a 6-inch pot, expect to see pink flowers and resulting fruit by the time it reaches about 18 inches tall. Strong growth spurts will bring more flowers and fruit.

When outdoor night temperatures fall below 60 degrees Fahrenheit, bring the star fruit indoors. Position it in a situation with as much bright light as possible and make sure that room temperatures do not fall below 60 degrees. If the plant drops a few leaves in the days after the transition, don’t worry. Indoors or out, water when the top few inches of soil feel dry. Higher humidity will improve the growth of these tropical trees.

Feeding Star Fruit

Fafard Natural & Organic Potting Mix pack

Star fruit trees grow most actively in spring and summer, so this is the time to fertilize with balanced, granular fertilizer, added at intervals according to manufacturers’ directions. Growth slows down during the winter months, so feeding can stop at that time. At winter’s end, just as you are about to start fertilizing again, prune back branches that seem weak or unshapely. Dwarf trees generally need relatively little pruning.

If you like the tropical taste of star fruit and relish a horticultural challenge, try adding a dwarf star fruit tree to your house plant menagerie. It may be the start of a tropical fruit tree collection.

(Click here to learn more about growing other tropical fruit trees indoors.)

Growing Tropical Fruits Indoors

Growing Tropical Fruits Indoors Featured Image
Dwarf Cavendish bananas and calamondins and are super tropical fruits for indoor growing.

Growing tropical fruits in Toledo (or Toronto or Trenton) may seem like the stuff of fantasy. It’s perfectly doable, though, thanks to the numerous dwarf tropical fruit trees that take well to containers and flower and fruit at a young age. A warm sunny outdoor location in summer, an equally sunny indoor niche in winter, a suitable watering and fertilizing regime, and a well-drained growing medium (such as Fafard Professional Potting Mix) will keep them happy and fruitful.

Indoor Citrus

The genus Citrus is particularly well endowed with container-friendly plants. Kumquats (Citrus japonica, aka Fortunella) are a stellar example. Visit your local supermarket during the winter holiday season, and you’re likely to find the orange-yellow, tart, bite-sized fruits of the popular kumquat variety ‘Nagami’. A number of other, lesser-known kumquats are well worth eating (and growing). The cultivar ‘Meiwa’ bears round, orange, 1¼ -inch fruits that are comparatively sweet and seed-free. Large, thin-skinned, orange kumquats deck the branches of another relatively sweet-flavored variety, ‘Fukushu’. In contrast, ‘Hong Kong’ produces numerous showy, scarlet, ¾-inch fruits with large seeds and scanty pulp. They’re great for ornament but not as good for eating.

Kumquat ‘Nagami’
Kumquat ‘Nagami’

Ripening in early winter, kumquat fruits typically remain on the branches until spring, providing decoration and snack possibilities well beyond the holidays. Small, starry white flowers perfume the air in late spring and early summer, and the lustrous, verdant, evergreen leaves are handsome year-round.

Fafard Professional Potting Mix pack

Calamondin (Citrus mitis) is what happened when a kumquat hybridized with a mandarin orange (Citrus reticulata). The result is a compact, repeat-blooming evergreen shrub that carries fragrant white flowers and small, chubby, tasty “oranges” throughout much of the year, with production peaking in winter. The fruits can be eaten fresh and make excellent preserves. Splashy cream-yellow markings adorn the leaves and immature fruit of the calamondin ‘Variegata’.

Meyer lemon (Citrus limon ‘Meyer’) is yet another citrus with admirable qualities. A small evergreen tree that can be easily maintained at 3 feet tall in a container, it produces several flushes of flowers and fruits throughout the year, peaking in winter and early spring. The 2- to 3-inch lemons have thin, golden-yellow rinds and relatively sweet, juicy, flavorful flesh that goes well in salads, stews, and preserves.  They also make a zingy snack.
Among the other edible citrus for containers are Key lime (Citrus aurantifolia), myrtle leaf orange (Citrus myrtifolia), and Rangpur lime (Citrus limon ‘Otaheite’). The takeaway (particularly if you have lots of container-gardening space) is that you don’t have to live in the tropics to enjoy a year-long harvest of lemons, oranges, and kumquats.

Growing Citrus

Citrus prefer ample sunlight, medium to high humidity, 40° to 60° F minimum temperatures, and moderate watering and feeding from spring to fall (with lower amounts in winter).

Prune off unwanted growth immediately after the fruiting season, in early spring.  Common indoor pests can be a problem. Watch for mealybugs, scale, whiteflies, and other common Citrus pests, particularly on stressed or over-fertilized plants. Cleaning plants up with insecticidal soap before bringing them back indoors in fall can help ward off these pests.

Indoor Guava

Pineapple guava flowers (Image by C T Johansson)
Pineapple guava flowers (Image by C T Johansson)

Guavas are another group of tropical New World evergreens renowned for their aromatic flowers and fruits, and several can be grown beautifully indoors.

Native to uplands of central South America, pineapple guava (Feijoa sellowiana, aka Acca sellowiana) works wonderfully as a container plant. Lustrous, leathery, silver-backed leaves clothe the upright, gray-barked stems of this handsome small tree. Sweet-scented, pale purple flowers with starbursts of maroon stamens open in late spring and early summer, followed by waxy, blue-green, egg-shaped fruits that cast an intoxicating fragrance as they mature in fall. Their pineapple-flavored fruits (with undertones of mint and apple) are at their best for only a few days after they fully ripen.

Pineapple guava plants require cool winter conditions (40° to 50° F minimum) and at least one cross-pollenizing companion plant for maximum flowering and fruiting. As with all the guavas described here, they appreciate a monthly application of organic fertilizer in spring and summer. Plants can be kept at 4 to 6 feet by removing overgrown stems in late summer.

Dwarf guava (Image by Logee's)
Dwarf guava (Image by Logee’s)

Common guava (Psidium guajava) also takes readily to container culture, fruiting reliably and repeatedly in warm, humid, sunny conditions (60 degrees Fahrenheit minimum). For home growing, choose the true dwarf guava (Psidium guajava var. nana). The fragrant white flowers with bottlebrush stamens recur throughout the year, giving way to pale green-skinned fruits that have delicious, musky-scented, deep pink flesh when ripe.

A vicious weed in many tropical regions outside its native Brazil, strawberry guava (Psidium cattleianum) is an exemplary container plant for colder latitudes, provided it’s spared from temperatures below 50° F. Small, spherical, red-skinned fruits with tangy, pale flesh appear in late summer and continue through winter in favorable locations. The fruits are preceded by fuzzy, white, sweet-scented flowers.  The variety lucidum (commonly known as lemon guava) has yellow-skinned, relatively tart flavored fruits. A small tree in the wild, Psidium cattleianum grows much more compactly in containers, typically topping out at 4 or 5 feet.

Other Indoor Tropical Fruits

Avocado 'Day' (Image by Logee's)
Avocado ‘Day’ (Image by Logee’s)

There’s a lot to explore in container-friendly tropical fruit trees beyond citrus and guavas, including loquat (Eriobotrya japonica), dwarf mango ( Mangifera ‘Pickering’), star fruit (Averrhoa carambola), and the ‘Tainung’ papaya (Carica papaya ‘Tainung’ ), which will begin fruiting on 2-foot plants. Many dwarf common-fig cultivars (Ficus carica), such as the super tiny ‘Petite Negra’ that starts fruiting on 12-inch plants, also grow well in a warm winter sunroom or conservatory. There are even mangoes, such as the golden mango ‘Nam Doc Mai’, that will grow well in large indoor pots.
Another favorite that’s easy to grow is the dwarf banana ‘Extra Dwarf Cavendish’ (Musa ‘Extra Dwarf Cavendish’). Once they reach 3-feet high, they will produce small trusses of delicious bananas year-round, if given high light, regular water, and warmth.

Banana ‘Extra Dwarf Cavendish’
Banana ‘Extra Dwarf Cavendish’

Then there are avocados (Persea americana). Many home growers will opt to start their own trees from pits, but this will result in large trees unfit for indoor growing. Instead, choose a dwarf tree such as the avocado ‘Day’. This compact selection and will produce small avocados from July to September. Bring them indoors in a brightly lit location through winter.

These fruits are best purchased as plants, but most are not readily available at your neighborhood nursery. To find them search for a specialty online plant source, such as Logee’s Plants for Home and Garden. Good online nurseries such as this offer a wide selection of compact tropical plants ideal for indoor container culture.

Potting Indoor Tropical Fruits

Most of these small trees sold in 4- to 6-inch pots, so plants are small at purchase time. Plant them in a slightly larger pot using Fafard Professional Potting Mix, and provide them with good light. Pots should have drainage holes and bottom saucers. Try to maintain even moisture and high humidity, and feed them with a tropical fruit tree fertilizer, as directed.
When the plants begin to outgrow their pots, upgrade them as needed for ample root growth. Those that are fruiting size, usually 4 to 5 feet, require relatively large pots.

Pot your tropical fruits now, and in a year or two, you will be harvesting your own home-grown tastes of the tropics.

Dwarf mangoes
Even mangoes come in dwarf forms!