K-State Research and Extension News
December 17, 2009
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Plants Don’t Care if the Wind Chill Tanks



COLUMBUS, Kan. – When wind chill temperatures plummet, gardeners chafe about their landscape and fruit plants’ odds for survival. Some gardeners actually worry too much.



“Cold can be a killer if people are growing marginally hardy plants or if air temperatures drop well below what’s usual where they live. Hard freezes are particularly destructive when plants aren’t fully dormant. But … ‘cold’ and ‘wind chill’ aren’t the same thing,” said Jake Weber, horticulturist with Kansas State University Research and Extension.



Wind chill only affects warm-blooded animals -- including people. It’s an indexed, scientific measure of how wind speed and air temperature combine to impact animal heat loss, Weber said.



“We know, for example, that our heat-loss rate will speed up as the air temperature drops. The faster the wind is blowing, however, the more dramatic that heat loss is going be,” he explained.



Wind chill has no meaning for plants, Weber added. Unlike warm-blooded animals, they don’t try to maintain a particular body temperature year-round.



Plants’ hardiness zone – the area in which they’re likely to survive winter – directly relates to a single factor: how low the area’s air temperatures typically go.



“That’s not to say winter winds can’t harm plants, too,” Weber said. “Wind accelerates plants’ moisture loss, and that can be a real problem in winter, especially for evergreens – plants that don’t quite enter dormancy. Wind also can crack ice-covered trees into a shattered mess and whip climbing roses until they snap.”



Bundling up protects people, head to toe, from both wind and cold, he said. But mulching just insulates plant roots and some grafts from winter’s air-caused temperature shifts. Fortunately, for healthy, sturdy plants growing in their hardiness zone, that’s often enough.



“Protecting weak, brittle or damaged limbs from winter’s wind is a separate and often more complicated issue. Gardeners simply have to do the best they can,” Weber said. “The effective approaches can range from site selection and pruning practices to wraps and stakes.”



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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by: Kathleen Ward
kward@ksu.edu
K-State Research & Extension News

Jake Weber is at 620-429-3849.