Poinsettia (Euphorbia pulcherrima), a colorful houseplant often recognized as a symbol of Christmas, produces attractive, red foliage and white flowers during the holiday season. Blooming plants are usually available for purchase in lawn and garden centers during the winter months. Gardeners often discard poinsettia plants after blooming ends, as they require significant effort to re-bloom, and replace them each year. When provided with the proper growing environment, you can coax plants to produce another batch of flowers, but it takes more than a little patience and vigilance.
Keep poinsettia plants in a sunny windowsill that receives at least six hours of bright sunlight each day. Maintain a constant temperature of 65 to 70 degrees F at all times for optimal growth. Never expose the plant to temperatures below 50 degrees F, as cold damage will occur.
Water whenever the soil feels dry to the touch, about once every seven to 10 days. Soak the soil thoroughly until moisture begins to exit the drainage holes at the bottom of the container, and then promptly remove any excess water.
Feed poinsettia plants once a month, beginning just after blooming ends, with an all-purpose houseplant fertilizer diluted to half the strength recommended by the manufacturer. Water lightly before and after applying to release the nutrients into the soil. Cease fertilization just before blooming resumes.
Cut the poinsettia back to about 8 inches in height during April or May. Keep in a sunny window and follow regular care procedures. The plant will appear unattractive during this time, but new growth will begin again after about one month.
Re-pot poinsettia plants in mid-June to provide additional room for growth and a fresh growing medium. Increase the size of the container by 2 to 4 inches and use a potting mix made of 2 parts potting soil and 1 part peat moss.
Keep the plant in complete darkness for 14 continuous hours each night beginning on October 1. Provide six to eight hours of bright sunlight during the day and temperatures between 60 and 70 degrees F. Continue for eight to 10 weeks to allow the flower buds to form properly and the plant will bloom in time for the holiday season. Resume normal care after flowering ends.