Finger lime

About Finger lime

Finger lime is a very thorny shrub or small tree from the subtropical rainforests of northern New South Wales and southeast Queensland in Australia. Its finger-shaped fruit, about 3 inches long, is packed with tiny round juice beads that pop like caviar, in green, pink or red depending on the variety. It shrugs off citrus greening better than most citrus, and some varieties stay small enough for a big pot.

No extension source we found gives a hardiness zone range. In Florida, finger limes came through a 2022 freeze with wind chills of about 21-32 F and recovered within a week, but UF says trees under 2 years old need freeze protection and that 'UF SunLime' handles cold better than 'UF RedLime'. The 9-11 range shown here is our estimate, matching other limes; treat it as a guide, not a rating.

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

• Set out plants: up to 2 weeks after the last frost

A potted tree goes outside after the last spring frost and is eased into full sun over about two weeks (Maryland Extension; Wisconsin says wait until temperatures stay above 50 F). UF found finger limes start to flower and fruit within a year of planting, with steady crops after the third year.

Soil

In a pot, a fast-draining, slightly acid citrus or palm-and-cactus mix; we found no finger-lime-specific soil guidance, so follow general container citrus advice (Mississippi State; UC Master Gardeners).

Pot it in a fast-draining, slightly acid potting mix (bark-based, or palm-and-cactus mix) in a container with drainage holes, never garden soil; in the ground, test the soil and keep the pH around 6.0-7.0 (Mississippi State; UC Master Gardeners; UGA).

Feeding

• First feeding after planting, once new growth starts (about 4 to 6 weeks): citrus fertilizer with micronutrients (about a 2-1-1 or 3-1-1 N-P-K ratio with iron, manganese and zinc, or a slow-release 12-6-6 or 12-4-6). Follow the label for a pot; in the ground, UGA starts a young tree with about 1/3 lb of 8-8-8 with micronutrients spread in a 30-inch circle and watered in. UF says finger limes get by on much less fertilizer than regular citrus, so stay at the low end of the label.
• Early spring each year, as new growth begins: citrus fertilizer with micronutrients (N-P-K about 2-1-1 or 3-1-1). Slow-release granules need 2 to 3 feedings a season; a water-soluble citrus food can instead go on about once a month from late winter to fall (Clemson; Maryland; UC Master Gardeners; Texas A&M).
• Early summer: citrus fertilizer with micronutrients. Repeat the spring feeding at the label rate and water it in (Maryland Extension).
• Late summer (the last feeding of the year): citrus fertilizer with micronutrients. Give the final feeding, then stop by early fall so new growth can harden before winter; in the ground, UGA says no fertilizer from August 1 to February 15.
• Any time young leaves turn yellow with green veins: chelated iron fertilizer or a sulfur soil acidifier. Apply as the label directs; this pattern usually means iron is short or the mix is not acid enough (Maryland Extension).

Don't feed through the winter indoors (Wisconsin and Minnesota feed only about April to September), and don't overwater or let the root ball dry out: too much water drops leaves and too little drops flowers (Maryland; Mississippi State). Finger limes need less fertilizer than standard citrus, so don't overfeed (UF/IFAS).

Harvest

At Riverside, California, finger limes ripen off and on all year with the most fruit in October to December; ripe fruit is roughly 2 to 4 inches long and its final skin color (green, yellow, red or purple-black) depends on the variety (UC Riverside). Wear thick gloves: UF calls the thorns wicked.

Finger limes bear year-round, with the main crop in November-December in California, when ripe fruit comes off in your hand.

Varieties (20)

Pests to watch for

Scale insects, Mealybugs, Twospotted spider mite, Aphids, Whiteflies, Citrus leafminer, Asian citrus psyllid

Diseases and problems

Root rot, Sooty mold

In the kitchen

The little juice beads are used as a tart, crunchy garnish for seafood, drinks and fancy dishes; the flavor is limey, and some describe hints of lemon and grapefruit (UF/IFAS; USDA-ARS).

Keeping it: In UF/IFAS trials, finger limes held up about three weeks at 50 F, better than at ordinary fridge temperature.

Safety: The sources we checked list no toxic parts, and we found no research-based guidance on use in pregnancy, drug interactions or allergies. The long, sharp thorns can injure hands and eyes.

Pets: Not listed by the ASPCA; the ASPCA does list orange, lemon, lime and calamondin as toxic to dogs, cats and horses because of essential oils and psoralens in the plant.