Tree · Rutaceae
Lime
Citrus × latifolia
Hand it plenty of sun, quick-draining soil, and steady heat, and it'll keep cropping for years.
Full sun
Every 5–10 days
USDA 9–11
8–20 ft · 2.4–6.1 m
Overview
The Persian lime is that seedless, smooth-skinned lime you'll spot at pretty much every market, a hybrid citrus that's grown for its sharp, aromatic juice. It turns into a good-looking small tree, getting to 8 to 20 feet (2.5 to 6 m) with a rounded canopy, and it carries fruit on and off through much of the year where things stay warm. Most people pick the limes while they're still green, because that's when the acid's at its best.
At its core this is a warm-climate tree, right at home in the ground across USDA zones 9 to 11 and just as happy in a pot anywhere colder so you can duck it out of the frost. It handles cold a bit better than the Mexican (Key) lime, but a hard freeze still does real damage. What does it actually want? Full sun, free-draining soil, and a break from biting wind.
Limes aren't fussy day to day, but a few things really do decide how it goes. Wet feet bring root and foot rot, the wrong soil pH locks out nutrients, and a short list of citrus diseases can undo a tree if you miss the early signs. Get the drainage and feeding right, though, and you've got a long-lived tree that pays you back for the care.
Care
The short version: full sun, free-draining sandy loam, and a deep but not-too-often drink once the top few centimeters dry, plus a feed through the growing season with a citrus fertilizer that carries the trace nutrients limes need.
Light
A lime tree really wants full sun, ideally 8 hours or more a day, if you want a decent crop. It'll put up with a little partial sun, but shade thins the canopy and cuts your harvest.
Water
Water deeply once the top few centimeters of soil dry out, then let it drain all the way. Established in-ground trees get by on less, while pots dry fast and might need water every few days in heat. The one thing you really don't want is waterlogged roots, which invite foot and root rot.
Soil
Go with well-drained sandy loam, because standing water is the quickest way to lose a citrus tree. A pH of 6.0 to 7.5 keeps the nutrients within reach, and it's the pH drifting too high that brings on those yellow, veiny leaves of micronutrient deficiency.
Temperature
Limes love warmth, roughly 32°F to 95°F (0°C to 35°C), and they'll grow year-round where it stays mild. They're tender to frost, though, so a cold snap means cover or a move indoors for potted trees.
Humidity
Average humidity of 40% to 60% suits a lime just fine, so there's no special number to hit. What matters more is good airflow through the canopy, since warm, still, humid air is exactly what greasy spot and other fungal diseases love.
Feeding
Feed through the active growing season, from spring into late summer, with a balanced citrus fertilizer that includes magnesium, manganese, zinc, and iron. Those micronutrients are just what limes tend to run short on, and a complete citrus feed heads off the yellowing before it even starts.
Pruning
Limes don't need much pruning at all. Take out dead, damaged, or crossing branches and any suckers below the graft union, and thin lightly after harvest to open the canopy. Wear gloves, because the peel and juice oils plus sun can blister bare skin.
Repotting
Move a container tree into a bigger pot every 2 to 3 years in spring. Roots circling the pot or poking out the drainage holes, water running straight through, and slowed growth with yellowing leaves all say it's time.
Size & spacing
A mature lime gets to 8 to 20 feet (2.5 to 6 m) tall and about as wide, so give it some real room to spread. In a pot it stays smaller, but it still wants air moving freely around the whole canopy.
When to plant
A lime tree just wants warmth and no frost, so put it out in spring once the soil and air have warmed up for real. Where it's warm it'll bloom on and off all year, and the main crop runs from summer into winter, with the fruit picked green for the sharpest juice.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Plant in spring after all danger of frost, once soil and air are reliably warm.
- Harvest: Blooms on and off year-round in warm climates; main harvest summer into winter, with fruit picked while green for highest acidity.
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
Most lime trouble starts on the leaves, so it's worth giving them a look pretty often. Some problems clear up fast with a bit of sanitation or feeding, but two of the diseases below are serious enough that you'll want to report them. Match what you see, then jump on it before it spreads to the rest of the tree.
Tan, corky scabs wearing yellow halos across leaves, twigs, and rind
This one's citrus canker, a bacterium that hitches a ride on wind-driven rain and dirty pruning tools. Wondering how to tell it from greasy spot? The corky lesions wear a yellow halo and show up on the fruit rind too, not just the leaves. Bag the infected growth, wipe your tools between cuts, and if canker's under quarantine where you live, let your local agricultural authorities know.
Fix:
- Remove and bag infected leaves and twigs
- Disinfect pruning tools between cuts
- Apply preventive copper sprays
- Report to local agricultural authorities in regulated/quarantine areas
Blotchy off-center yellowing, twigs dying back, and little bitter fruit
Here's the tough one, citrus greening, also called huanglongbing, and it's wiped out citrus across whole regions. The Asian citrus psyllid carries it, and the giveaway is a blotchy mottle that runs right across the leaf midrib instead of matching side to side, plus lopsided fruit. There's no cure, unfortunately, so you'll need to remove and destroy an infected tree, keep the psyllid down, and report any find to agricultural authorities.
Fix:
- There is no cure; remove and destroy infected trees to protect others
- Control Asian citrus psyllid with approved insecticides or oils
- Report finds to agricultural authorities
Yellow blotches on top and greasy brown blisters underneath the leaves
What you're looking at is greasy spot, a fungus that gets going in warm, muggy weather and lives on the old leaves rotting under the tree. See a lot of leaf drop in late summer and fall? That's the tell. The fix is pretty simple, so rake up and get rid of the fallen litter, open the canopy for air, and time a copper or oil spray for early summer.
Fix:
- Rake up and destroy fallen leaves to cut inoculum
- Apply a copper fungicide or horticultural oil in early to mid summer per label
- Prune to improve air circulation
Leaves going yellow but veins staying green, worst on new growth
If the leaves go yellow but the veins stay green, and it's the youngest leaves that show it first, that's a micronutrient shortage of iron, manganese, or zinc, usually because the soil pH is too high or the roots are sitting wet. Older leaves yellowing all over? That's a nitrogen thing instead. Spray a chelated micronutrient feed, swap to a citrus fertilizer that carries those trace elements, and sort out the drainage.
Fix:
- Apply a chelated micronutrient foliar spray
- Switch to a citrus fertilizer that includes micronutrients
- Correct drainage and avoid overwatering
Toxicity
The juice and flesh are totally safe to eat, but the rest of the tree's another story. The peel, leaves, and seeds carry essential oils and psoralens that upset a pet's stomach and can blister human skin in sunlight. Keep prunings, peels, and seeds away from animals, and pop on some gloves when you handle the tree.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
If a cat chews the peel, leaves, or seeds, you'll usually see vomiting, loose stools, and a dull, low mood. The oils can leave its mouth or skin a bit sore too.
Dogs Mild
A dog that gnaws on peel, leaves, or seeds tends to get an upset stomach and some diarrhea, and might look a bit flat and depressed afterward.
Horses Mild
Those same peel and leaf oils that bug the pets can leave a horse off its feed and queasy, so it's smart to keep prunings and dropped fruit out of the paddock.
Rabbits Caution
The aromatic oils in peel and foliage just don't sit right with a rabbit's sensitive gut, and there's really no reason to chance it, so skip the lime altogether.
Livestock Caution
Goats and other stock might nibble a fallen fruit and be fine, but a belly full of bitter peel and leaves can turn the stomach, so fence them off from prunings and windfalls just in case.
Birds Caution
A taste of the flesh is usually no big deal, but the strong oils in peel and leaves can bother a small bird, so offer just a little clean fruit and keep the rind away.
People Fruit safe
Good news in the kitchen: the juice and flesh are a staple and safe to eat. The catch is the skin, since peel oils and juice in sunlight can raise a blistering 'margarita burn,' so just rinse your hands after handling.
Wear gloves when pruning or zesting; lime juice or peel oils on skin exposed to sunlight can trigger phytophotodermatitis ('margarita burn'), a painful blistering rash.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Persian lime goes by more than one name, and you'll see a couple of forms at nurseries. So here's what those labels actually mean.
Bearss
Bearss is the everyday Persian lime you'll find grown all over the US, especially in Florida, and it's a nearly thornless, seedless tree with smooth-skinned fruit that ripens from green to yellow.
Tahiti
Tahiti's just another name for the same triploid seedless lime as Bearss, a vigorous tree that handles the cold better than the Mexican (Key) lime.
Companions
A lime grows best beside flowers that pull in the predators of its pests, and worst with grass crowding the trunk where rot likes to start.
Plant near
Sweet alyssum: Its tiny flowers attract hoverflies and parasitic wasps that help control aphids and psyllids.
Marigold: Draws beneficial insects and may deter some pests around young trees.
Keep apart
Turf grass grown up to the trunk: Lawn competes for water and nutrients and holds moisture against the trunk, raising foot-rot risk; keep a mulched, grass-free zone.
How to propagate
Limes get multiplied by the nursery method of grafting or by slower home techniques, though only grafting gives you the full benefit of a rootstock.
GraftingDemanding
Spring to early summer when the bark slips · 1 to 3 years to bearing
Grafting is how the nurseries do it, and honestly it's the smart way. Bud or graft your lime onto a disease-resistant, often dwarfing rootstock in spring or early summer while the bark still slips, and the young tree gets vigor, cold tolerance, and disease resistance before it starts bearing in 1 to 3 years.
Air layeringModerate
Warm growing season · Several months to root, then 1 to 2 years to establish
Air-layering is something you can pull off at home during the warm growing season, and it takes several months to root and then 1 to 2 years to settle in. The catch? An own-rooted tree skips the rootstock, so it ends up more cold-tender and more prone to disease.
Stem cuttingsModerate
Semi-hardwood cuttings in late spring or summer · 1 to 2 years
Semi-hardwood cuttings taken in late spring or summer will root and grow to a usable size in about 1 to 2 years. Just like air-layered trees, these own-root plants miss out on the cold hardiness and disease protection a rootstock would give them.
Myths
Limes are just unripe lemons.
Nope, limes and lemons are separate citrus, and Persian lime is its own hybrid, Citrus x latifolia. Growers pick limes green for their sharp acidity, but the fruit turns yellow when fully ripe, which is nothing like an unripe lemon.
Plant a seed straight out of a lime and you'll get a real Persian lime tree.
Not really, since Persian lime is a seedless triploid that almost never sets a viable seed, so nurseries graft it instead. Any stray seedling you did manage to sprout would not come true to the parent tree.
The whole citrus plant is seriously poisonous to your dog and cat.
The fruit flesh really just causes a mild stomach upset, nothing scary. It is the essential oils and psoralens packed into the peel, leaves, and seeds that the ASPCA flags as toxic, not the juicy part people eat.