Keeping Poinsettias Through the Year - December 13, 2006
Jeff Schalau, County Director, Associate Agent, Agriculture & Natural Resources
Arizona Cooperative Extension, Yavapai County
During the holiday season, we see poinsettias everywhere. Many of us buy a plant for decorative touch or as a gift for someone we are visiting. The poinsettia industry has grown around this holiday tradition. Today, poinsettias are one of the most important floricultural crops produced in the United States. Grown primarily as a potted plant for the Christmas season, total U.S. wholesale poinsettia production was valued at $252 million in 2003.
Here are some hints to keep your poinsettias looking perky and colorful well beyond the holiday season. Poinsettias thrive on bright, sunny natural daylight; at least six hours daily is recommended. Placement near a sunny window is ideal. To prolong the bright red of the bracts, temperatures ideally should not exceed 70° F during the day, or fall below 65° F at night. Be sure to avoid placing the plants near drafts, fluctuating air currents, excess heat and dry air from appliances, fireplaces or ventilating ducts. Chilling injury will occur if poinsettias are exposed to temperatures below 50° F. Frost will kill them.
Poinsettias do best with a moist soil condition, not too wet and not too dry. Water the poinsettia thoroughly when the soil surface feels dry to a light touch. The best indication of a thorough watering is when the water begins to seep through the drain holes at the bottom of the inner pot. Be sure to discard any excess water, as poinsettias left sitting in water may suffer from permanent root-rot damage.
It is not necessary to fertilize your poinsettias when they are in bloom during the holiday season. However, after 6-8 weeks, a balanced, all-purpose household plant fertilizer mixed ½-strength will help maintain the rich, green foliage color and promote new growth. Repeat once more in another 6-8 weeks.
Here are some tips for those that would like to keep their poinsettia growing until next holiday season. At the end of April or early May, when the bracts age and begin to turn a muddy green, cut the plant back to about 8 inches. The amount you cut from the top will depend on the shape of the plant. After you cut the plant back, it will probably look rather stark, with bare branches and bluntly cut woody stems. Keep the plants near a sunny window. You may place your plants outdoors where they can bask in the warmth of summer when the outside night temperatures are warmer. Continue to water the plants regularly during the growing period. Fertilize every 3 to 4 weeks throughout the spring, summer and fall months with a well-balanced fertilizer mixed ½-strength.
Around June 15th you may wish to transplant your poinsettias into larger pots, about 2" to 4" bigger than the original inner pot. Use a soil mix that incorporates a considerable amount of organic matter such as peat moss. Immediately after transplanting, be sure to water thoroughly.
Starting October 1, the plants must be kept in complete darkness for 14 continuous hours each night. Moving the plants to a dark room or placing a large box over them can accomplish this. During this period, the plants require 6 to 8 hours of bright sunlight and night temperatures between 60° and 70° F. If the temperature is too high or too low, the setting of the flower buds may be delayed or halted.
The blooming process may also be delayed or disrupted by any stray light that may shine near the plants during the critical darkness period. Keep this up for 8 to 10 weeks for full color development. If this sounds like a lot of work, it is. It certainly gives me a healthy respect for the nursery industry. If all this sounds like too much work, then support the horticulture industry by purchasing new plants each year.
The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at firstname.lastname@example.org and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.
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Last Updated: December 7, 2006
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