If you bring your calamondin orange tree inside during the winter, place it by a bright sunny window where it can get as much sun as possible. Fertilize lightly during winter months, using a half-strength portion of a water-soluble product designed for citrus trees every six weeks. Wiping down the leaves regularly will keep away mite and scale infestations, and a light misting of the leaves every few weeks will help them retain humidity. Water when the soil is dry 2 inches below the surface, but don't allow the tree to stand in a puddle.