Use with caution
Star fruit is safe for most people but is high in oxalic acid and contains a neurotoxin (caramboxin) that healthy kidneys filter out. People with kidney disease, or anyone on dialysis, should not eat star fruit or drink its juice unless cleared by their doctor, as even a small amount can cause serious harm.
Averrhoa carambola 'Arkin'
fruitArkin is the leading sweet carambola, the cultivar that turned star fruit from a tart curiosity into a popular dessert fruit. Its waxy, golden-yellow fruit has five prominent ribs, so a crosswise slice forms a perfect star - as ornamental on a plate as it is to eat. The crisp, very juicy flesh is mild and sweet-tart with a hint of citrus, eaten skin and all with no peeling or seeds to fuss over. Arkin is self-fruitful and precocious, and the tree is an attractive, multi-branched evergreen that bears young and over a long season, making it one of the easiest and most decorative tropical fruits for a warm garden.
Sun
full sun
Water
Every 5 days
Harvest
~18 months
to first harvest
Difficulty
easy
Lifecycle
perennial
Comes back every year
Spacing
20-30 ft apart
Planting Depth
Top of the root ball level with or slightly above the soil
Soil pH
4.5-7.0
Soil Type
Acidic, well-draining
Hardiness Zones
Zones 9 – 13
When to Fertilize
Every 30-60 days when young; several times a year when mature
Fertilizer
Complete fertilizer with magnesium and minor elements
Carambola is a true tropical that wants full sun, warmth, and good drainage. Young trees are killed near 27 to 29F and mature trees near 20 to 24F, suiting zones 9b to 11. It adapts to many well-drained soils and prefers a moderately acid to neutral pH of about 4.5 to 7; above pH 7 it shows nutrient deficiencies that need chelated minor elements. Plant 20 to 30 ft from buildings and other trees, and water regularly from flowering through harvest (one to two times a week without rain), since drought stress drops flowers and fruit. Feed young trees a quarter to half pound of a complete fertilizer (about 6-8 percent N with magnesium) every 30 to 60 days, scaling up to several pounds a few times a year on mature trees. The shallow-rooted tree benefits from mulch and wind protection.
Direct sow
Apr 15
Projected first harvest
Jun 24 · Year 2
Year 1
Good neighbors that attract beneficial insects or deter pests
Proactive ways to stop trouble before it starts — tap a name with an arrow for its full guide
Treat stems and leaves with horticultural oil and prune out encrusted wood
Adults notch leaves and larvae feed on roots - manage ground cover, use beneficial nematodes, and remove fallen fruit
Pierce and blemish fruit - bag developing fruit, clear weedy hosts, and hand-pick
A fruit and leaf fungus in wet weather - prune for airflow, avoid overhead watering, and clear mummified fruit
Arkin begins bearing remarkably fast - within about 10 to 14 months of planting - and fruit matures 60 to 75 days from fruit set, with the main season running June through February. Pick when the fruit turns from green to yellow in the furrows between the ribs while the rib tips are still just greenish; it does not sweeten after picking, so let it color fully on the tree. Handle gently, since the thin ribs bruise. Eat fresh, sliced into salads, or juiced.
Very light at about 31 calories per 100 g, with 2.8 g fiber, 34 mg vitamin C, 133 mg potassium, and antioxidants. The whole fruit is edible, crisp, and refreshing - just be aware of the kidney-disease caution above.
Star fruit is safe for most people but is high in oxalic acid and contains a neurotoxin (caramboxin) that healthy kidneys filter out. People with kidney disease, or anyone on dialysis, should not eat star fruit or drink its juice unless cleared by their doctor, as even a small amount can cause serious harm.
For educational and informational purposes only — HomeSown is not medical, health, or other professional advice. Always positively identify any plant before handling or eating it; some plants, and some parts of otherwise-edible plants, are toxic. Consult a qualified professional before consuming or otherwise using any plant, especially if you are pregnant, nursing, taking medication, or have a health condition.
Year 2