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Growing Regions and Zones

The plant hardiness zones given in this site are based upon those from the USDA provided by the United States National Arboretum.

They provide an interactive zone map on the following website: http://www.usna.usda.gov/Hardzone/ushzmap.html

These zones are based upon the average minimum temperature range.

For a full range of temperatures and example cities in an interactive map, see the following web page:

USDA Interactive Map

There are many benefits and drawbacks associated with the use of hardiness zones, see the following web page for an in depth discussion:

http://en.wikipedia.org/wiki/Hardiness_zone

A basic overview of average minimum temperatures associated with the zones is given in the following table:

Zone

Average Annual Minimum Temperature

Zone

Average Annual Minimum Temperature

1

< -50°F (45.6°C)

6

< -10° to 0°F (- 23.3 to -17.8°C)

2

 -50° to -40°F (-45.6 to -40°C)

7

< 0° to 10°F (- 17.7 to 12.3°C)

3

 -40° to -30°F  (- 39.9 to -34.5°C)

8

< 10° to 20°F (- 12.2 to -6.7°C)

4

 -30° to -20°F (- 34.4 to -28.9°C)

9

< 20° to -30°F (-1.2 to 40°C)

5

 -20° to -10°F (- 28.8 to -23.4°C)

10

> 30° (-1.1°C)

The table below has links to various hardiness zone maps:

Africa

Europe

Russia

Australia

Great Britain and Ireland

South America

Canada

Japan

South Africa

China

New Zealand

World

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