Meg Lynch, Editor of Horticulture Magazine, blogs about her mother's "Christmas" cactus blooming for Thanksgiving. Which is why I prefer to call them "Holiday" cactus. They bloom during the Fall/Winter when the days are getting shorter. She says:
Short days (and long nights) trigger their flowering. My mother keeps hers in a room not frequented at night. It is dark there from sundown to sunup, and they reliably set buds and bloom in late fall. This year they were just in time for pumpkin pie.Couldn't ask for a better centerpiece for the table. That's her mother's plant above.