Calamansi (Citrus microcarpa) – also sold as calamondin, calamondin orange or calamansi lime – is a small evergreen citrus grown for sharp, intensely fragrant little fruits. It is a staple of Filipino cooking and, in cooler countries, one of the most popular citrus for growing in a pot.
It is also unusual among citrus in one important way, which is where most people’s questions start.
Can you really grow calamansi from seed?
Yes – and this is the key point. Calamansi seeds are easy to germinate, and you do not need to graft the tree in order to get fruit.
That is genuinely unusual. With most citrus, growing from seed is discouraged because grafting is required to guarantee the fruit type, the quality and a reasonable wait to first harvest – a seed-grown lemon or orange can be a slow, thorny disappointment. Calamansi does not carry that penalty in the same way, which is why starting it from seed is a recommended route rather than a compromise. For a home grower, that means a free tree from the pips of a fruit you already bought.
Sowing calamansi seeds step by step
- Timing. Sow in spring. In a warm climate you can also sow in autumn.
- Use fresh seed. Citrus seed does not store well – it loses viability as it dries. Seed straight out of a ripe fruit is best.
- Soak older seed. If the seed is not fresh, soak it in water for an hour or two before sowing.
- Sow shallow. Set the seed about 1 cm deep and cover it lightly.
- Keep it moist. The soil must stay consistently moist through germination – drying out at this stage is the usual reason seeds fail.
- Keep it warm. Calamansi is a tropical to warm-subtropical plant; warmth drives germination.
Sow several seeds rather than one. They are free, germination is never guaranteed, and you can keep the strongest seedling.
Caring for young plants
- Light: full sun to half shade – it will grow in either, but it prefers sun and fruits better with it.
- Water: an average to generous amount. In pots it needs less than in open ground, so judge by the soil.
- Soil: slightly acidic, loamy and free draining. Keep it moist through the fruiting season and mulch the surface.
- Feeding: work organic matter, humus and fertiliser into the soil.
Calamansi is a frost-free plant that will nevertheless survive light frost. It suits hardiness zone 10+, and zone 9b with the right care and protection.
Planting out
Dig a hole larger than the pot’s root ball, mix fertiliser and organic material into the soil going back in, then plant.
- Cold climate: plant in spring, so the tree has the whole warm season to establish.
- Hot climate: spring or autumn. Avoid the coldest and hottest months – extremes at planting time cause damage that shows up much later.
One detail worth doing in hot regions: where fierce summer sun strikes the exposed main trunk, whitewashing the trunk with lime paint prevents sunburn damage to the bark.
Growing calamansi in a pot or indoors
This is where calamansi really earns its popularity. It takes well to containers, is very often trained as a bonsai or dwarf, and can be grown indoors as a houseplant – provided it gets plenty of light.
Practical points for pot culture:
- Keep it deliberately small. In a container the aim is a compact tree, not maximum size.
- Water controls growth. Bonsai growers manage the tree’s vigour largely through watering – useful to know if you want to hold it at a set size.
- Light is the limiting factor indoors. A calamansi in a dim room will survive and sulk; it needs the brightest position you have to flower and fruit.
- Drainage is critical. Citrus in pots dislike soggy soil far more than they dislike being slightly dry.
In open ground expect roughly 2–4 m, occasionally up to 6 m, with a medium to slow growth rate. That modest, slow growth is precisely what makes it manageable in a pot for years.
Flowering, pollination and fruit
The flowers are white and grow in clusters, and the fruit is small – about 1–4 cm – ripening to orange. Growing more than one tree increases the chance of pollination and a heavier crop, so if you have room for two, plant two.
Calamansi is also frequently grown purely as an ornamental: a compact evergreen carrying white flowers and bright orange fruit at the same time is a genuinely decorative plant, quite apart from what you do with the harvest.
Using the fruit
Calamansi fruit is edible, but sharply sour raw – it is used the way you would use a lime rather than eaten like an orange.
- Juice – the classic use, for drinks, dressings, marinades and dipping sauces.
- Fruit leather.
- Sugared or candied peel.
- The peel for fragrance.
The peel is edible but bitter, so it is much better cooked, or dried with sugar, than eaten raw.
Pruning
Prune in spring or summer, removing:
- dead branches,
- branches crossing or growing into each other,
- growth that has become too dense.
Shape the tree so the fruit is easy to reach – particularly important if yours is one of the thorny cultivars, since not all calamansi carry thorns.
Pests and problems
The pests are the standard citrus set:
- Citrus leaf miner – silvery winding trails inside new leaves, worst on soft young growth.
- Aphids – clustering on shoot tips and flower buds.
- Ants – a warning sign in themselves, since they farm and protect aphids.
- Citrus foot rot and citrus gummosis – trunk and base problems, encouraged by soil or mulch piled against the trunk and by constantly wet bark. Keep the base clear and dry.
Splitting fruit is worth knowing about: when the fruit splits or bursts, it is a watering signal – the tree needs more water, and more importantly a steadier supply, since erratic watering during fruiting is what causes it.
For the complete plant profile see our Calamondin (calamansi) growing page.
