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Desert Diary


Virtually everyone knows that freezing occurs at 32°F, so it's not surprising that people get a bit antsy about their garden plants when the temperature dips below that. What many forget, however, is that 32° is the freezing point of pure water, and there's relatively little such around. Most water has various amounts of dissolved minerals. After all, the main reason that salt is used on icy roads is that a mixture of salt and water has a much lower freezing point than water alone, melting the ice and clearing the roadway.

Formation of ice crystals is the main cause of damage and resultant death of tissues. The liquid portions of a plant, though, include various dissolved substances, and thus the temperature at which ice crystals form is usually far below 32°. The result is that, in our relatively benign desert climate, some plants are not only able to survive temperatures that may drop into the teens, but even manage to thrive during late winter to grace our landscape with small patches of new green.
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Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.


Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.