Poinsettias cannot be cold! You should even shield them from the cold on your way home from the store. When you get them home, they will last longest in bright light. If you keep them in low light, they will drop their leaves.
Poinsettias are a holiday favorite, but many people ask how to make their poinsettia rebloom. BUT the regimen you need to follow to rebloom poinsettias is so strict we don’t recommend it. Just toss your spent poinsettia on the compost pile and call it a day. If you really, really want to try to rebloom your poinsettia you will need three things: a warm house, a dark closet, and dedication!
Read on for the full directions and timetable:
April 1st: Cut your poinsettia back to about 8" in height. Water regularly and fertilize with Neptune’s Harvest Fish and Seaweed Fertilizer, or another organic, balanced fertilizer.
May 15th (Or after all chance of frost has passed and night temperatures average 55° F or above): Place your poinsettia outside in indirect light, on a porch, or in dappled sunlight, and continue regular watering. Fertilize with the fish and seaweed emulsion every 2 to 3 weeks.
June 1st: You may transplant your poinsettia into a larger pot. Select a pot no more than 4 inches larger than the original pot. Keep up the fertilizing!
July 1st: Pruning may be required during the summer to keep plants bushy and compact. (You could do it later in the summer, but do not prune later than September 1.) Keep the plants in indirect sun and water regularly.
Here’s the tricky part:
October 1st: Your poinsettia must be kept in complete darkness for 14 continuous hours each night! Stray light of any kind, such as from a streetlight or household lamps, could delay or entirely halt the re-flowering process. Avoid stray light by moving the plant to a totally dark closet at six o’clock each evening and take it out at seven o’clock each morning.
During October, November and early December, poinsettias require 6 - 8 hours of bright sunlight daily, with night temperatures between 60 - 70° F. Temperatures outside of this range could delay flowering.
Continue the normal watering and fertilizer program. Carefully following this regime for 8 to 10 weeks should result in a colorful display of bracts and blooms for the holiday season!