Poinsettias begin to set buds and produce flowers as the nights become longer. Beginning now, keep your plants in complete darkness for 14 continuous hours each night by moving it into a dark room or placing a large box over it. During the day, allow 6-8 hours of bright sunlight.
Water as needed and fertilize weekly, following label instructions. Continue this for about 8-10 weeks, and your poinsettias should develop a colorful display of holiday blooms!