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Frost temporarily damaged the bermudagrass plots in the previous photograph. The intricate pattern may be due to thermodynamic effects, e.g., "Where does cold air settle on a clear, still night?" . . . chaos theory. A similar pattern may sometimes be seen in localized dry spots on a golf green. In the example, the presence of damage in the background plot, but not the foreground, is due to a higher mowing height and a higher rate of N fertilization which made frost damage worse.
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| There are more serious cold-weather damages to warm-season turfgrasses. Between -7 and -9 C (16 to 20 F), St. Augustinegrasses winterkills, with slight differences in cold tolerance among cultivars. Floratam has been shown in the laboratory to have no hardening, thus it is not surprising that in one experiment depicted above, there was no relationship between days after planting and subsequent winter kill. The graph presents winter survival as a percent of canopy of late-planted Floratam plugs in 26 Florida counties following the 23-24 December 1989 cold snap. Numbers in parentheses following a county name are the number of days of establishment prior to cold. Only intermediate-level counties are labelled. |
