What is the best way to keep a poinsettia alive from year to year?
Treat it as any houseplant, but don’t overwater it or subject it to too much sunlight. To encourage it to bloom for Christmas, make sure the plant has at least 12 hours of darkness, with nighttime temperatures between 60 and 68 degrees Fahrenheit. Keep the plant under these conditions until buds develop and the bracts (petals) begin to color. When they bloom, take the plant to a sunny, draft-free room. The bracts will color up within 6 to 10 weeks and may continue to bloom until Easter.