10/10/1995

Disturbing Poinsettia Sleep May Add Color to Holiday Season

AUBURN, Ala. - Interrupting the night of poinsettias may provide more colorful Thanksgiving, Christmas, and New Year's, according to Auburn University researcher Bridget Behe.

Behe, who is an associate professor of horticulture at Auburn University, began the project with Raymond Kessler, assistant professor of horticulture, to determine some alternative ways to increase the marketing window for poinsettias, which normally are potted to bloom around Christmas.

Most varieties of poinsettias require 9-10 weeks of short days to bloom. However, Freedom is an earlier blooming variety, and Behe chose this variety, so that she could force poinsettias potted at the same time to bloom over a longer period, allowing growers more flexibility in marketing blooming poinsettias, without requiring multiple potting times.

Poinsettias naturally bloom during periods of long nights. Interrupting the "sleep" of Freedom poinsettias with artificial light from 10 p.m. until 2 a.m. makes the plant think it has had two short days and two nights, which delays the plant's bloom.

The project is being conducted at the Ornamental Horticulture Substation in Mobile. In the project, Freedom poinsettias are separated by a black plastic partition. Plants on one side are kept in the dark, and on the other side lights are used to provide the 130 footcandles of light necessary to break one long night into two short nights.

"Poinsettias are very sensitive to light. In fact, even a street light near a greenhouse can destroy a crop of these plants," Behe noted. In the study with Freedom poinsettias, we really are trying to determine how long we can keep these poinsettias vegetative and still get flowers. And, the ultimate goal is to provide a wider window of opportunity in which producers can provide colorful poinsettias," the Auburn researcher explained.

"We move the poinsettias every three, five and six weeks, working them back into the long night cycle. If all goes as expected, the last plants under the lights should bloom last," noted John Olive, superintendent of the 22-acre Ornamental Horticulture Substation, which is a research unit of the Alabama Agricultural Experiment Station System.

If keeping poinsettias awake for four hours during long nights consistently delays bloom, the result might be a better selection of colorful poinsettias throughout the Thanksgiving until New Years holiday season.

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News from:

Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)

Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu
by Roy Roberson

October 10, 1995