Growing Calamondin or Calamansi: Crop Info
and Cultural Practices

The calamondin tree ( x Citrofortunella microcarpa, syn. Citrus microcarpa, Citrus mitis and x Citrofortunella mitis), is also known as China orange and golden lime; calamansi, kalamansi, kalamonding and limonsito in the Philippines; jeruk peres, jeruk kasturi, and jeruk potong in Indonesia; limau kesturi and limau chuit in Malaysia; and sommapit, somchit and manao-wan in Thailand.

This fruit crop probably originated in China as a result of natural crossing between mandarin and kumquat. It is now widely grown in India and all over South and Southeast Asia, and almost everywhere. In some countries, it is a popular house plant.

This plant is a shrub or small tree with a long taproot, 2-7.5 m tall. Trees grown from seed start fruit production 5-6 years after planting, but this is shortened to 3 years or less by planting asexually propagated seedlings.

Flowering and fruiting is year round, with a peak harvest season lasting for 3 months which falls during the months of August to October in the Philippines.

The calamondin fruit is well known for its acid juice which is used as a flavoring for dishes comprising seafood and meat. Commercially, this sour-tasting juice is processed into concentrate, drinks, and various products.

Mature calamondin fruits are popular for their sour juice.

Fruits are round, greenish-yellow with a diameter of about 2-4.5 cm, and reaches full maturity in about 5 months after flowering. Like other citrus species such as pummelo and mandarin, the calamondin fruit is rich in phosphorus, calcium, iron and vitamin C.

A 3-year old calamondin tree may yield 0.75 kg of fruits. A 6-year old tree may bear up to 5000 fruits with an average yield of 10 kg; a 10-year old, 50 kg.


How-to Guide / Cultural Practices


Soil and Climatic Adaptation
Calamondin or kalamansi is adapted to warm climates but it can also grow in cool, frost-free areas. It can grow in any soil type but prefers a well-drained, sandy or clay loam soil rich in organic matter, pH 5.5-7.0, in locations with annual rainfall of 1500-2000 mm. It has moderate tolerance to drought and shade but cannot tolerate excessive moisture and strong winds.

Plant Propagation
Calamondin can be propagated by seed or by asexual method. Seedlings raised from seed are true-to-type and spiny. Clonal seedlings can also be propagated by stem cutting, air layering or marcotting, budding and grafting. For large scale production, shield and chip budding, cleft or wedge grafting, and rooting of stem cuttings under continuous mist or in non-mist propagation chamber have been practiced.

Upper shoot of a mature calamondin tree, also called kalamansi.

For growing in the backyard or in containers (pots), air layering or marcotting is recommended. Marcotted calamondin trees are spineless with small stature, and readilly bear fruits. (Click to read the procedures in marcotting)

Pot Selection and Planting
Seedlings should be planted at the onset of the rainy season in places where there is a pronounced dry and rainy season. But in places where rainfall is evenly distributed throughout the year, where there is irrigation, or in backyard and pot gardening, planting can be done anytime.

For field planting, the seedlings are carefully laid on holes dug at least 40 cm wide and deep. The removed topsoil is replaced, preferably mixed with compost. Watering should be done daily.

For pot planting, any container can be used depending on preference based on such considerations as durability, aesthetics, cost, and final size of the tree. Pots with top diameter in excess of 8 inches (20.3 cm) are generally recommended for shrubs. Potting can be started with small pots and progressively changed to bigger ones as the plant becomes bigger. The potting medium should be fertile, rich in organic matter and loose, which can be obtained by mixing topsoil, sand and compost (click to read Growing Dwarf Potted Bamboo).

If grown as a houseplant, sufficient light should be provided.

Planting Distance
The planting distance for growing calamondin in the orchard under monoculture ranges from 4-6 m in square, rectangular or triangular system. This is equivalent to a calculated population density of about 278-719 trees per hectare, depending on plant-to-plant distance and the planting system to be adopted. With 5 m x 5 m spacing in square system, the population density per hectare will be 400.

For potted plants, the pot-to-pot distance is dictated only by the size of the plant canopy which should not be allowed to overlap in order to maximize light penetration.

Portion of fruit-bearing calamondin. The small white objects are flowers.


Fertilization
Nitrogenous fertilizers like urea should be applied at the rate of 50-100 g per tree starting 1 month after planting and every other 6 months. This rate is increased to 200-300 g per tree in the second year. When the tree starts bearing fruits commercially, 350-400 g of complete fertilizer is applied, the rate increased correspondingly as the tree becomes bigger.

The fertilizers can be distributed into 6-8 holes around the tree and timed with the onset and end of the rainy season or just before the start of flowering. The incorporation of organic fertilizers in the fertilization plan will also benefit the plant by providing micronutrients.

With potted calamondin, it is better to apply slow-release fertilizers. Likewise, the use of 1-2 percent solution of a mixture of nitrogen and complete fertilizer may be an alternative, to be applied regularly as a soil drench.

Pruning

Pruning should be employed to remove excess, diseased and dead branches. To maximize light penetration, 3-5 lateral branches in spiral arrangement are allowed to develop starting from about 1 ft (30 cm) from the base of the trunk. Pruning may be done also to limit expansion of the tree canopy.

To enhance the increase in the size of the tree that will be capable of producing more fruits, fruit development in the early years may be deferred. This involves flower and fruit pruning or the deliberate removal of flowers and fruitlets to allow the concentration of food into the developing vegetative parts.

Floral Induction
Calamondin trees can be forced to flush and flower by heavy watering. This can be done 1-2 months prior to the normal flowering time. However, plant response is usually more elicited when the trees have been stressed by dry months prior to floral induction.

Plant physiologist Nasir Malik of Kika de la Garza Subtropical Agricultural Research Center, Weslaco, Texas, has also developed a temperature-controlled growth chamber which was effective in inducing grapefruit trees to produce new flushes. Trees that were placed in the growth chambers for 10 weeks flowered almost immediately when transferred to the greenhouse (click to read update on Citrus Greening).

Pests and Diseases Control
Numerous insect pests attack the calamondin tree. These include the citrus bark borers, aphids, and scales. Red mites which are arachnids may also become serious pests. In orchards, regular monitoring for pest incidence and spraying of insectides or miticides should be a part of the management program, especially during flushing period.

A serious disease is leaf mottling which is internationally known as citrus greening, transmitted by the Asian citrus psyllid (Diaphorina citri). The psyllids live and reproduce on new shoots and need to be eradicated in order to prevent citrus greening. Likewise, quarantine measures should be effected to prevent the introduction of diseased or psyllid-infested citrus plants, as well as the popular ornamental plant orange jessamine or kamuning (Murraya paniculata), being a favored host of the psyllid.

Other common diseases are gummosis, citrus canker and citrus scab. Gummosis is caused by Phytophthora fungi and usually occurs where there is mechanical damage to the stem or where there is either lack or excess fertilizer. The disease is characterized by a dark sticky exudate or gum which oozes out of the infected part of the branch or trunk. Prompt spraying or painting of fungicide solution should be done directly to the diseased area.

Harvesting
Mature fruits are harvested either by hand or by clipping with a pair of scissors. To prolong shelf life, a portion of the pedicel is left attached to the fruit and injury to the skin should be avoided. Storage at 8-10 C with relative humidity of 90% will further extend the freshness of the fruits up to 3 weeks.

References

http://www.da.gov.ph/tips/calamansi.html, accessed December 26, 2010.

Verheij, E.W.M. and R.E. Coronel (eds.). 1992. Edible fruits and nuts. Plant Resources of South-East Asia No. 2. Bogor, Indonesia: Prosea Foundation. pp. 117-119.

(Ben G. Bareja 2010)


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