Lime

Tree facts

Scientific name

Citrus aurantiifolia

Origin

Southeast Asia

Tree size

Key lime 6–13 ft and shrubby; Persian lime 15–20 ft

Growth rate

Medium

Sun

Full sun, at least 6–8 hours

Soil

Any soil that drains well, including sand and the limestone of South Florida. Never waterlogged.

Soil pH

6.0–7.5

Pollination

Self-fertile; one tree is enough

Cold hardiness

The most frost-sensitive citrus: Key limes are hurt near 32°F, Persian limes near 28°F

USDA zones

10–11 (Persian into 9b)

Years to first fruit

2–3 for a grafted tree

Season

Year-round

Water

About every 7 days once established, without rain; more in heat, in pots and while young

Feeding

About every 60 days, Feb–Oct

Pruning

Mar–May

Taste

Sharp and sour; Key lime is more aromatic, with a slightly bitter edge

Nutrition

Good source of vitamin C

Is lime safe to eat? Edible and toxic parts

What you can eat

• Juice
• Zest of the peel
• Makrut lime leaves, in Thai and Southeast Asian cooking

Toxic parts and cautions

• Take care: Lime is the worst citrus for sun burns on the skin. Juice or peel oil on the skin, followed by sun, can cause blistering burns or dark patches that last for months (phytophotodermatitis). Wash hands and any splashes with soap before going outside, especially when making drinks outdoors.
• Good to know: Key and makrut limes have sharp thorns. Wear gloves when picking and pruning.

Pets: The peel, leaves and seeds contain essential oils (limonene, linalool) and psoralens that can cause vomiting, drooling and skin irritation in dogs and cats. A bite of the flesh is usually harmless.

How to eat and enjoy lime

• Key lime pie
• Limeade, margaritas and mojitos
• Ceviche and fish tacos
• Thai and Vietnamese dishes, dressings and dipping sauces
• Makrut leaves in tom yum soup and curries
• Indian lime pickle

Lime varieties (5)

• Key · also Key lime, Mexican, Mexican lime, West Indian

  A small, round, thin-skinned lime with intense aroma, the lime of Key lime pie.

  Origin: Southeast Asia; long grown in the Florida Keys and Mexico · Taste: Very sour, aromatic · Season: Year-round, heaviest in summer · Size: Small, 1–2 in

  Thorny, seedy and very cold-tender. Ripe fruit turns yellow.

• Makrut · also Kaffir, Makrut lime, Thai lime

  A separate species (Citrus hystrix) grown for its glossy double leaves, a key flavor in Thai cooking. The bumpy fruit has little juice; its zest goes into curry pastes.

  Origin: Southeast Asia

  Many growers now call it makrut, since kaffir is an ethnic slur in southern Africa. Thorny and cold-tender.

• Palestine Sweet · also Palestine sweet lime, Indian sweet lime

  A low-acid lime with mild, sweet juice, popular in India and the Middle East.

  Origin: South Asia and the Middle East · Taste: Sweet, mild, low acid

  Botanically Citrus limettioides.

• Persian · also Tahiti, Tahiti lime, Bearss lime, Bearss

  The seedless, juicy grocery-store lime, larger and less sharp than Key lime.

  Origin: Uncertain; probably a hybrid of Key lime and lemon · Taste: Sour and clean · Season: Year-round, heaviest in summer · Size: Medium

  Nearly thornless and hardier than Key lime. Botanically Citrus × latifolia.

• Rangpur · also Rangpur lime, Mandarin lime

  Not a true lime but a mandarin-lemon hybrid with orange skin and flesh and very sour, lime-like juice.

  Origin: South Asia (Rangpur, now in Bangladesh) · Taste: Very sour, with a mandarin aroma · Size: Small

  Hardier than true limes; also used as a citrus rootstock.

Pests and diseases to watch for

• Whiteflies

  Clouds of tiny white flies when a branch is shaken; yellowing leaves and sooty mold.

  What to do: Insecticidal soap or horticultural oil on leaf undersides.

• Citrus greening (HLB)

  Blotchy, uneven yellowing that isn't the same on both halves of a leaf; small, lopsided, bitter fruit that stays green at the bottom; twig dieback.

  What to do: There's no cure. Keep the tree well fed with a complete citrus fertilizer and micronutrients to slow decline.

  A regulated disease in Florida, Texas, California and elsewhere. If you suspect it, contact your county extension office or the state agriculture department.

• Citrus canker

  Raised, corky brown spots with a yellow halo on leaves, twigs and fruit; fruit may drop early.

  What to do: Copper sprays protect new growth and young fruit.

  Regulated in several states. Report suspected cases to your extension office.

• Citrus leafminer

  Silvery, winding tunnels in young leaves, which curl and twist.

  What to do: Mostly cosmetic on mature trees; leave them be.

• Phytophthora root rot

  Small, pale, wilting leaves, thin canopy and branch dieback; roots are black and brittle instead of white.

  What to do: Water less and improve drainage.

• Scale insects

  Small bumps, waxy or shell-like, on stems and leaf veins; sticky honeydew and black sooty mold below.

  What to do: Scrub small colonies off with a soft brush.