I am looking for an average percent of damage caused by frost by
temperature and by time of frost.  For example by temp: 26 degees
causes 40 % damage to grape vine, 27 degrees causes 20 percent damage
to vine, etc...   And example by date would be: From march 1st to
March 15th if a frost occurs there will be approximately 30 % damage,
If in early April frost will cause 20 % damage.

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Clarification of Question by bwhit-ga on 14 Mar 2003 12:26 PST

Need answer for 31, 30, 29, 28, 27 degrees fahrenheit, and months
February through end of May

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Request for Question Clarification by nellie_bly-ga on 14 Mar 2003 14:59 PST

What kind of grape and what geographic location?

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Request for Question Clarification by lmnop-ga on 15 Mar 2003 17:11 PST

Yes, the grape types vary enormously...some are very cold hardy and
others quite sensitive. As well, other factors (wind and humidity)
will enter in. Not sure what to suggest, but maybe there is a way to
pose the question differently. For example, why do you need to know
this information? There might be a more direct route to the answer.

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Clarification of Question by bwhit-ga on 16 Mar 2003 13:29 PST

The varieties that I need the information for are primarily Cabernet
Sauvignon and Merlot.  The question applies to a feasibility study for
frost protection systems and the probability of frost.  The % damages
will be used as follows

(%damage by date + % Damage by Temp)x (Average tons peracre x Average
Price per ton)x Probability of Occurence of Frost = Loss($) from
frost.

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Clarification of Question by bwhit-ga on 16 Mar 2003 13:30 PST

Geological location is San Luis Obispo County California, in the Paso
Robles Creston Areas

Hi again,
It seems I can't get enough time to really give you what you need at
this point, but here's a quick suggestion. First, try going to this
page and finding a couple of phone numbers for California growers and
ask your question. I bet you get some cold hardiness figures quickly.
Second, try to determine what the temperature and humidity facts are
for your site...it's hard to be very specific if not familiar with the
topography there, the elevation and exposure to sun and wind, etc.
Finally, you might need to be satisfied with a generalization you can
draw by comparing the site's data to what people tell you. Things just
have a little too much variability to them to be definite in terms of
percentages as you would like. Good luck!
Here's the Cornell list:
http://www.cce.cornell.edu/programs/finger-lakes-grape/Nurseries.htm