Greets all and a merry and safe christmas to all of you.

I have noticed in several posts the the term Zone 9 or Zone 5 etc is
mentioned when describing locality. Being from Australia, I have no idea
what this means exactly. Could someone point me to a site or resource that
explains this Zoning system as it would further clarify much of the advice
given in this fine newsgroup.

Thanks.

Mark,

This is reference to the United States Department of Agriculture (USDA) cold
hardiness zones - areas of the US grouped by the lowest temperatures
normally seen. http://www.usna.usda.gov/Hardzone/ushzmap.html is US map -
click on the listed by zone and you will get the temperatures and some
representative plants that will survive in the ground at these temperatures.
The link http://www.anbg.gov.au/hort.research/zones.html extends the concept
to Australia and I know it has been extended to Europe and some other areas.
There has been extensive discussion on the list in the past including the
fact that plants in pots are not nearly as hardy and that the highest
temperatures and number of cool to cold days are important for many plants.
I hope this helps.

Marty

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Mark,

This is reference to the United States Department of Agriculture (USDA) cold
hardiness zones - areas of the US grouped by the lowest temperatures
normally seen. http://www.usna.usda.gov/Hardzone/ushzmap.html is US map -
click on the listed by zone and you will get the temperatures and some
representative plants that will survive in the ground at these temperatures.
The link http://www.anbg.gov.au/hort.research/zones.html extends the concept
to Australia and I know it has been extended to Europe and some other areas.
There has been extensive discussion on the list in the past including the
fact that plants in pots are not nearly as hardy and that the highest
temperatures and number of cool to cold days are important for many plants.
I hope this helps.

Marty

************************************************** ******************************
++++Sponsored, in part, by Boon Manakitivipart++++
************************************************** ******************************
-- The IBC HOME PAGE & FAQ: http://www.internetbonsaiclub.org/ --
+++++ Questions? Help? e-mail +++++

areas of the US grouped by the lowest temperatures normally seen.

Not exactly. The zone refers to the AVERAGE (mean) minimum winter temperature
in the past 10 or 15 years. If the lowest winter temperature one year was -10
and the next year was -20, the average is -15 and you are in Zone 5. This
system does not give you any other climate data, which has led to some
misunderstanding.
I had the chart posted & was about to send it when the phone rang. I'll try
again.
Sorry, the link is broken. I can give it to you from memory.
Zone 1 - below -50 F, I don't have the conversion handy for the coldest zones.
zone 2 - -40 to -50 F.
3 - -30 to -40 F.
4 - -20 to - 30 F.
5 - -23 to -28 C.
6 - -18 to -23 C.
7 - -12 to -18 C.
8 - -7 to -12 C.
9 - -1 to -7 C.
10 - +5 to -1 C. Frost about every other year.
11 - Average above 5 C. Pretty much guaranteed frost-free.
Some books postulate a Zone 12 in the equatorial tropics.
As far as I know, Australia is primarily in USDA zones 8 to 10, but they have
their own system.

Iris,
Central NY, Zone 5a, Sunset Zone 40
"A tree never hits an automobile except in self defense." - Woody Allen

areas of the US grouped by the lowest temperatures normally seen.

Not exactly. The zone refers to the AVERAGE (mean) minimum winter temperature
in the past 10 or 15 years. If the lowest winter temperature one year was -10
and the next year was -20, the average is -15 and you are in Zone 5. This
system does not give you any other climate data, which has led to some
misunderstanding.
I had the chart posted & was about to send it when the phone rang. I'll try
again.
Sorry, the link is broken. I can give it to you from memory.
Zone 1 - below -50 F, I don't have the conversion handy for the coldest zones.
zone 2 - -40 to -50 F.
3 - -30 to -40 F.
4 - -20 to - 30 F.
5 - -23 to -28 C.
6 - -18 to -23 C.
7 - -12 to -18 C.
8 - -7 to -12 C.
9 - -1 to -7 C.
10 - +5 to -1 C. Frost about every other year.
11 - Average above 5 C. Pretty much guaranteed frost-free.
Some books postulate a Zone 12 in the equatorial tropics.
As far as I know, Australia is primarily in USDA zones 8 to 10, but they have
their own system.

Iris,
Central NY, Zone 5a, Sunset Zone 40
"A tree never hits an automobile except in self defense." - Woody Allen