what 2 things trigger a christmas cactus to bloom

Christmas cacti have an interesting way of blooming. It's triggered by a combination of darkness and cool temperatures. If you want to force your Christmas cactus to bloom, you can simulate the conditions it needs by keeping it in a dark room for 12 hours a day and then moving it to a cool room for 12 hours a day. This will trick the plant into thinking that winter is coming, and it will start to bloom in a few weeks.