Ideally, cacti need as much sunshine and air circulation to bloom as well as grow. If you do not have at least four to six hours of filtered sunlight indoors, move the cactus to the patio or a place outdoors where it will receive some sun and air. Do this procedure for about once or twice a month. Windows with northern exposure or areas with too much shade are not the best spots for cacti. The best spot for cacti living indoors is directly in front of the window.