I saved last year's poinsettia. How do I get it to flower for Christmas?

Poinsettias are short-day plants.  Short-day plants grow vegetatively during the long days of summer and produce flowers when days become shorter in fall.  In order for poinsettias to flower for Christmas, they must receive complete darkness from 5 p.m. to 8 a.m. each day from early October until the bracts show good color, usually around early December.  (Most poinsettia varieties require 8 to 10 weeks of short days to flower.)  Gardeners can protect their plants from light by placing them in a closet or by covering with a cardboard box.  When using cardboard boxes, cover any openings to insure complete darkness.  Exposure to any kind of light between 5 p.m. and 8 a.m. will delay or possibly prevent flowering.  During the remainder of the day, the poinsettias should be placed in a sunny south window.  Keep the plants well-watered and fertilize every 2 weeks during the forcing period.  While poinsettias are difficult to flower in homes, proper care can reward home gardeners with a colorful plant for the holiday season.