Friday, January 03, 2014

Baby it's cold outside .... or will be.

We are expecting the coldest temperatures my vineyard has ever seen over the next several days.   Highs on Monday and Tuesday may not get out of the minus teens Fahrenheit. Low temperatures will approach -20° F to -25° F (-29° C to -32° C).

NWS forecast
Mon Jan 6 forecast from NWS on Friday Jan3.
 While most of the grape cultivars I have planted should be okay, some will be on the edge of having some damage.

Below is a table of cultivars I grow, and the listed "hardiness temperature".  Hardiness temperatures are from this page.

Cultivar Hardiness Temperature
Foch -25° F / -32° C
Frontenac -35° F / -37° C
Marquette -35° F / -37° C
PetitePearl* (non producing) -32° F / -35° C
LaCrosse -25° F / -32° C
St Pepin -26° F / -32° C
LaCressent -36° F / -38° C
Prairie Star -40° F / -40° C
Frontenac Blanc * (non producing) -38° F / -39° C
Seedless Concord* -25° F / -32° C
Somerset Seedless (non producing) -30° F / -34° C
*The source for the hardiness temperatures for these varieties were found elsewhere.

Several things will determine how my vines pull through.  Including but not limited to:
  • Grape cultivar.  (obvious one, some vines are genetically better adapted to surviving cold.)
  • health of vine going into dormancy ( a sick weak vine will not be able to tolerate cold as well.)
  • age of vine   (younger trunks and cordons may be injured, and may need to be trained up from the roots.)
  • temperatures/weather immediately proceeding severe cold.   (Warm temperatures immediately preceding cold will de-acclimate the vine, and make vine more susceptible to damage. )
  • severity, and duration of the cold weather (another obvious one)
  • previous years crop load  (vine puts too much energy into ripening crop load, and may not store enough energy to come out of dormancy well in spring)
  • harvest time  ( a late harvest does not give the vine much time to put energy away before dormancy)
Of these factors,  harvest time and crop load last year may be impact my vines the most.   Crossing my fingers that everything goes fine.