A calamondin tree is one of the easiest citrus to grow in the US, especially in a pot. This compact hybrid, also sold as calamansi or calamondin orange, flowers and fruits young, often bears in containers just a few feet tall, and handles indoor winters better than most citrus. Grow it in the ground in USDA zones 9 to 11, or in a container anywhere if you can give it six or more hours of sun in summer and a bright window or grow light in winter. Feed it a citrus fertilizer with micronutrients from spring through late summer, water when the top inch or two of mix is dry, and keep it above freezing, and it will produce small, tangy fruit for much of the year.
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In this guide
Key Takeaways
- Outdoors year-round in zones 9–11; in pots anywhere, brought inside before frost.
- Needs 6+ hours of direct sun outdoors, or the sunniest window plus a grow light indoors.
- Use a fast-draining citrus or cactus-and-citrus mix in a pot with drainage holes.
- Water deeply when the top 1–2 inches are dry; never let roots sit in water.
- Feed with a citrus fertilizer containing magnesium, iron, zinc and manganese every 4–8 weeks in the growing season.
What Is a Calamondin?
Calamondin (Citrus × microcarpa, also listed as × Citrofortunella microcarpa) is generally considered a cross between a mandarin and a kumquat. It is widely grown in the Philippines, where the juice of the fruit, called calamansi, is a staple in cooking and drinks. The fruit is about 1 to 1.5 inches across, with thin, easy-peel orange skin and very sour, juicy flesh, a bit like a cross between a lime and a tangerine. Like kumquats, the peel is sweet, and some people eat small fruit whole.
The tree is upright and dense, with small, glossy evergreen leaves and very fragrant white flowers. In the ground in warm climates it can reach 10 to 20 feet; in containers it is easily kept at 3 to 6 feet. It is one of the more cold-tolerant citrus, handling brief dips into the low 20s°F once established, though fruit and young trees are damaged at higher temperatures. If you enjoy calamondin, see our guide to growing a kumquat tree, a close relative. For more fruiting and ornamental trees, browse our trees and shrubs guide.
Growing Calamondin in the Ground
In zones 9 to 11, mainly Florida, the Gulf Coast, southern Texas, Arizona and much of California, calamondin makes an attractive small tree or hedge.
- Site: Full sun, sheltered from cold winds. A south-facing spot near a wall adds warmth in borderline zone 9.
- Soil: Well-drained sandy or loamy soil, slightly acidic to neutral. Avoid low spots where water stands. On heavy clay, plant on a raised mound.
- Spacing: 8 to 12 feet from other trees and structures.
- Planting: Set the root ball slightly above surrounding soil, backfill with native soil, water deeply, and keep mulch a few inches away from the trunk.
- Frost protection: Cover young trees with frost cloth on nights forecast below about 28°F, and water the soil before a freeze.
Growing Calamondin in Containers
Most US gardeners grow calamondin in pots so they can move it indoors in winter. It is among the best citrus for this; our general guide to growing citrus indoors covers the basics that apply to all types.
Pot
Start a young tree in a 10- to 12-inch pot and move up one size, 2 to 4 inches wider, every two or three years in spring. A mature container tree does well in a 16- to 20-inch pot. Drainage holes are essential. Plastic or fiberglass pots are lighter to move than ceramic; put large pots on a rolling plant caddy.
Potting mix
Use a bagged citrus mix or a cactus-and-citrus mix, or blend a quality potting mix with about one-third pine bark fines and perlite for drainage. Standard moisture-retaining potting soil stays too wet for citrus roots, especially indoors in winter.
Light
Outdoors in summer, give at least six hours of direct sun. Indoors, place it in front of the sunniest south- or west-facing window. If leaves drop and growth stalls in winter, add a full-spectrum LED grow light for 12 to 14 hours a day. Move trees outdoors in spring after nights stay above about 50°F, starting in shade and moving into full sun over a week or two to avoid leaf scorch.
Watering
Calamondin likes steady moisture but not wet roots. Water thoroughly until it drains from the bottom when the top 1 to 2 inches of mix feel dry. In summer heat, outdoor pots may need water every day or two; indoors in winter, once every 7 to 14 days is common. Empty saucers after watering. Signs of overwatering are yellowing leaves, leaf drop and a sour smell from the mix; underwatering shows as curled, dull leaves and dropping fruit.
Feeding: Choosing a Citrus Fertilizer
Citrus are heavy feeders, and container trees lose nutrients each time you water. Use a fertilizer made for citrus, which typically has a higher nitrogen ratio plus magnesium, iron, zinc and manganese. Those micronutrients prevent the yellowing between leaf veins that is so common in potted citrus. You can find options by searching for citrus fertilizer on Amazon, and our roundup of the best citrus fertilizers compares granular, liquid and spike types.
- Granular slow-release: Apply every 6 to 8 weeks, or as labeled, from early spring to late summer.
- Liquid or water-soluble: Every 2 to 4 weeks at label rate during active growth. Easy to control in pots.
- Winter: Reduce or stop feeding indoors in winter when growth slows, unless the tree is under strong grow lights and actively growing.
- In-ground trees: Feed three or four times a year, in late winter, spring, early summer and late summer, following the label for tree size.
If leaves turn pale or develop yellow patterns despite feeding, see our guide to why citrus leaves turn yellow.
Flowering and Fruiting
Calamondin often blooms several times a year, and a single tree may carry flowers, green fruit and ripe fruit at the same time. Fruit takes many months to ripen, turning from green to orange. Outdoors, bees pollinate it, though calamondin can set fruit on its own. Indoors, you can improve fruit set by brushing open flowers with a small, soft paintbrush every few days, moving pollen from flower to flower.
Harvest when fruit is fully orange and slightly soft for maximum juice, or pick while still green-orange for the sour calamansi flavor many recipes call for. Clip fruit with scissors rather than pulling, which can tear the skin. Young trees may drop a lot of small fruit; this is normal thinning.
Pruning
Calamondin needs little pruning. In late winter or early spring, remove dead or crossing branches, and shorten long shoots to keep a container tree compact. Remove any shoots growing from below the graft union if the tree is grafted; these come from the rootstock. Many calamondins are grown on their own roots from cuttings, so they may not have a graft.
Repotting
Repot every two to three years in spring, just as new growth starts, or when roots circle the inside of the pot and water runs straight through. Slide the tree out, tease apart circling roots and trim any that are black and mushy. Set it in the new pot at the same depth it grew before, with the top of the root ball an inch below the rim, and fill around it with fresh citrus mix. Water thoroughly and keep it out of harsh afternoon sun for a week. If the tree is already in the largest pot you can manage, root-prune instead: trim an inch or two off the sides and bottom of the root ball, refresh the mix and return it to the same pot.
Propagating Calamondin
Calamondin roots more readily from cuttings than many citrus. In late spring or early summer, take 4- to 6-inch cuttings from semi-firm new growth, remove the lower leaves, dip the cut end in rooting hormone and insert it into a mix of perlite and peat or coir. Cover with a clear plastic bag or dome to keep humidity high, and keep it warm and in bright, indirect light. Roots usually form within several weeks. Trees grown from seed take much longer to fruit and may vary, so cuttings or nursery trees are the better route for a fruiting plant.
Overwintering Indoors
- Bring the tree inside before nights drop below about 40°F.
- Check leaves and stems for pests and hose the tree down before bringing it in.
- Place it in the brightest window, away from heating vents.
- Expect some leaf drop as the tree adjusts to lower light; it usually stops within a few weeks.
- Raise humidity with a pebble tray or by grouping plants, and water less often than in summer.
Pests and Problems
- Scale: Brown bumps on stems and leaf undersides, often with sticky honeydew. Scrape off by hand and treat with horticultural oil.
- Mealybugs: White cottony clusters; dab with rubbing alcohol on a cotton swab.
- Spider mites: Fine webbing and stippled leaves, especially indoors in dry winter air. Rinse foliage and use insecticidal soap.
- Aphids: On new growth in spring; spray off with water or use insecticidal soap.
- Leaf drop: Usually from sudden changes in light, temperature or watering. Keep conditions steady.
- Fruit drop: Often from inconsistent watering or heat stress.
Many of the same care steps apply to other container citrus. Our Meyer lemon tree care guide is a good companion if you grow both.
Frequently Asked Questions
Is calamondin the same as calamansi?
Yes. Calamansi is the common name in the Philippines; calamondin is more common in US nurseries. Both refer to the same small, sour citrus.
Can you eat calamondin fruit?
Yes. The juice is very sour and used like lime or lemon juice in cooking, drinks and marinades. The peel is sweet and can be candied or used in marmalade.
How cold can a calamondin tree tolerate?
Established in-ground trees can survive brief drops into the low 20s°F, but young trees, flowers and fruit are damaged at higher temperatures. Bring potted trees indoors before frost.
Why is my calamondin dropping leaves indoors?
Usually low light, overwatering or a sudden change in conditions after moving indoors. Give it the brightest window or a grow light, let the top inch or two of mix dry before watering, and keep it away from heating vents.
How long until a calamondin produces fruit?
Nursery trees often flower and fruit within their first year or two, even in small pots. Fruit then takes several months to ripen on the tree.