Christmas cactus grow in indirect bright light. The leaves may get burnt by direct sunlight and the insufficient light might also result in no flowering. Locate the position of the plant close to a filtered sunlight-based window-east windows are the best. Throughout the time of the year when flowers are in bloom, daily exposure to light would assist the buds to grow in the right manner. Light conditions should not be changed abruptly, this may put undue stress on the plant that will result in the dropping of the buds and this means that you are unlikely to get yearly blooms.