Calamansi: Everything You Need to Know About Calamondin Citrus Fruit

Watch out, yuzu: Calamansi is coming for you. In the ever-fickle focus of the trend-obsessed digital culinary world, fragrant yuzu remains, for now, the darling of internet searches (according to my quick query on Google Trends). But curiosity about calamansi, a small, sour, sweet-skinned citrus, is piquing. If not peaking (sorry). Possibly native to China, but ubiquitous in the Philippines and Indonesia, this petite citrus is widely cultivated in Southeast Asia. There, it is often harvested when mature but still green, with an interior that is already bright orange. It is far less common Stateside, where the fruit is also known as calamondin. Here, ripe yellow-skinned calamansi is available seasonally from a handful of specialty growers, and the trees are available to buy from some growers. They can be grown in pots, or planted in-ground. They bear fruit around year four.

Here’s what to expect from calamansi, and how to use this aromatic and tart fruit.

Photography by Marie Viljoen.

Calamansi-slash-calamondin has many other common names, including must lime and Philippine lime. Botanically, it is Citrus x microcarpa, and is thought to be a natural hybrid: Its tart interior speaks kumquat; its aromatic skin, mandarin.

Calamansi has a thin skin and minimal pith, like a Meyer lemon. Despite its tiny size, it is intensely juicy. Its copious seeds are reminiscent of yuzu (and, like yuzu’s, they are used in folk remedies as well as commercial skincare products).

Calamansi trees seem to be one of the less demanding citrus* to grow in cold climates. While the tropical tree must be overwintered indoors in climates colder than USDA growing zone 10, it seems happier with less than the usual prescribed full sun (which means a minimum of six hours, uninterrupted, a hard condition to meet indoors). My own tree was inherited last year from a friend who left Brooklyn to travel the world, and in her apartment it spent its green, lush life facing a very bright exterior wall, with no direct sun at all. It did not bloom or fruit. But leaf out, it did. On my summer terrace it flowered minimally, but made no fruit. I think more sun outdoors this year will produce better results. (Other city growers have the opposite problem.)

* More demanding indoor citrus? Meyer lemons, hands down. (Another citrus that requires less sunlight, since it is also a forest tree, is Thai lime, or makrut—Citrus hystrix.)

Like all potted citrus, calamansi grown in a container needs exceptional drainage. I use a 50:50 mix of potting soil and cedar shavings (shredded cedar mulch also works). Plant the tree in a pot only an inch or so wider than the grow-pot it arrived in. If the pot is too big the soil tends to stay moist too long, and too much moisture is death to most indoor plants. Water deeply, meaning: until the water runs from the drainage holes. Never allow the pot to sit in a pool of water. And water again when it is almost dry. This may take a week or more. A moisture meter is very helpful. The ideal spot for a citrus tree is in the sunniest window you have. Failing that, bright natural light will ensure healthy green leaves, but possibly not flowers and fruit.

For an in-depth primer on citrus in pots, see: 14 Things Nobody Tells You about Indoor Citrus Trees