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Proposed Frost Tolerances for Cranberries
(From a table done by C.J. DeMoranville, UMass, 1997)
Spring Cranberry Frost Tolerances
Appearance of the bud
Early Black & Howes
Ben Lear & Stevens
Spring dormant (bud reddish)
18 F
20 F
White bud stage (loss of dormant color in bud) 
20 F
22 F
Slight loosening of bud scales (no bud swell) 
22 F
25 F
Bud swell (cabbage head or popcorn stage)
2mm bud 
25 F*
27 F
Bud elongation (Bud is growing out/up) 
27 F** 
29.5-30 F
Roughneck (more than 1/2" new growth)
through hook stage 
29.5-30 F
29.5-30 F
* After 5-7 days, increase tolerance to 27 degrees F even if no change in appearance.
** After 5-7 days, increase tolerance to 29.5-30 degrees F even if no change in appearance.
 Fall Cranberry Frost Tolerances
Maturity Level
Early Black
Howes
Stevens
Ben Lears
Deep blush on exposed surface
27 F
27 F
27 F
27 F
Deep blush
26 F
26 F
26 F
26 F
Red
25 F
25 F
25 F
25 F
Deep red
23 F
23 F
23 F
24 F
Maroon
(1-2 weeks later)
23 F
20 F
22 F
24 F
Over-ripe
(end of October)
23 F
23 F **
23 F **
24 F
 ** loss of tolerance when over-ripe
Please note that each variety will reach a given stage on a different date.  Generally, Early Black and Ben Lears will both color early and Howes and Stevens will color later.  This tolerance chart is based on color development, which is used as a visual guide to ripening, a chemical and physiological process.  In some years, lower tolerances were found.  However, we cannot predict when this will occur so conservative figures are presented here.  In each of three years, cranberries showed tolerances at least as low as these for the stages listed.

If you have comments or questions about this page,
contact Charles Armstrong at: charlesa@umext.maine.edu
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These pages are currently being maintained by the Pest Management Office, University of Maine Cooperative Extension. Page Last Modified: 04/11/08