Climate Zones.

J.E. Shields
Fri, 28 Oct 2005 06:52:26 PDT
John Bryan, Jaime, Roger, Lee, et al.,

To answer John's original question directly, yes, I believe that the USDA 
cold zones are useful and should be retained.

What to add to them is the problem.  The American Hort. Society heat zones 
would be a good start.  Then add in maps of annual rainfall.

That is a start.  Nothing will make decisions about growing 100% foolproof 
for novice gardeners, and nothing will keep old hands from experimenting.

Besides nighttime minimum temperatures for the AHS heat zones, one needs to 
add local effects for urban islands of heat.  I live 25 miles from the 
center of a medium-large sized urban agglomeration.  We are routinely 2 to 
5 degrees F cooler than in the city, summer and winter.

But you should hurry John, because it looks like the climate is changing 
and the existing tables will become obsolete in a few more years.  Spring 
is coming a week to 10 days earlier now than it did 25 years ago.

Jim Shields
in central Indiana
USDA cold zone 5
AHS heat zone 6
40 inches of precipitation per year

At 09:49 AM 10/28/2005 +0200, you wrote:
>Ahh, Roger,
>hard but true words!  We are always seeking a simple solution to the
>complexities of life.  I didn't realize that the Arnold Arboretum (a truly
>wonderful place to visit!) was behind the original Zones.
>In the end, Zones are nothing but a guideline and one must not only know his
>local conditions, but understand them as well!
>Jamie Vande

Jim Shields             USDA Zone 5             Shields Gardens, Ltd.
P.O. Box 92              WWW:
Westfield, Indiana 46074, USA
Tel. ++1-317-867-3344     or      toll-free 1-866-449-3344 in USA

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