The calamondin is a miniature hybrid orange tree that's made for indoor growing. The calamondin (X citrofortunella microcarpa) grows no more than 3 feet in height and spread, blooming in white, fragrant flowers at least twice per year, followed by small, tart, edible orange-like fruits. The calamondin is most commonly grown as an ornamental plant rather than a fruit tree, but you can use the fruits it produces in similar ways that you would use limes or lemons.
Position your calamondin in bright, full sunlight, or the brightest, warmest light that you can provide indoors. Maintain air temperatures around your calamondin of 65 to 85 degrees Fahrenheit, but no colder than 55 degrees.
Water your calamondin only when the top quarter of the potting soil dries out slightly. Soak the calamondin's root ball thoroughly until the water begins to drain freely from the bottom of the pot.
Feed your calamondin once each month during the spring and summer with a high-acid liquid fertilizer, or one made for miniature or indoor citrus trees, that contains micro-nutrients. Feed the calamondin once every three months during the rest of the year, according to the instructions on the fertilizer's label.
Repot your calamondin orange tree when it becomes pot-bound, using an acidic, well-draining potting soil. Repot the calamondin in late winter or early spring, just before new growth begins.