Care for a Christmas cactus plant by placing it in bright light during the day with plenty of dark periods. Keep the plant humid, water it regularly at the crown where the stem meets the roots, and avoid splashing the foliage.
In order to care for a Christmas cactus, make sure that it gets bright but indirect sunlight. During the summer, place it in a shady spot outside or at a window indoors. During the winter, place the plant in a completely dark area for 14 hours at a time with only eight to 10 hours of daylight. The cactus needs to be in a room or garage with temperatures between 50 to 55 degrees Fahrenheit. It needs six weeks of these cool temperatures and long night hours to blossom.
Because the Christmas cactus is a tropical plant, keep it in a humid environment by placing a tray of wet pebbles below it or a tray of water nearby. Water it regularly, but let the top 1 inch of soil dry out before watering it again. Fertilize the cactus every few months from the spring through October, and prune away any dead or damaged limbs. If pests infest the plant or root rot develops, repot the plant.