| USDA
Plant Hardiness Zones
The USDA information is published as a
map officially named the USDA Plant Hardiness Zone Map, often referred
to as gardening or climate zones. It is the most commonly used
planting guide nationally. When shopping for plants online, this is the
hardiness zone information offered.
How to
Use the Map
Zones 2-10
in the map have been subdivided into light- and dark-colored sections (a
and b) that represent 5 F (2.8 C) differences within the 10 F (5.6 C)
zone. The light color of each zone represents the colder section;
the dark color, the warmer section. Zone 11 represents any area
where the average annual minimum temperature is above 40 F (4.4 C).
Areas above an arbitrary elevation are traditionally considered
unsuitable for plant cropping and do not bear appropriate zone
designations. There are also island zones that, because of
elevation differences, are warmer or cooler than the surrounding areas
and are given a different zone designation. Note that many large
urban areas carry a warmer zone designation than the surrounding
countryside.
Before
investing in your garden
It is
important when shopping for live plants for your garden or landscape
that you know which gardening zone applies to your area. Make sure
that the nursery you are considering for your purchases will only ship
plants to you that will survive in your climate zone at a time of year
when these plants can be planted or transplanted. Many trees
or flowers cannot be planted during certain times of year. Most
nurseries only deliver live plants in the spring and in the fall and
very rarely in the summer months.
| 1 |
Below
-50 F |
Below
-45.6 C |
Fairbanks,
Alaska; Resolute, Northwest Territories (Canada) |
| 2a |
-50
to -45 F |
-42.8
to -45.5 C |
Prudhoe
Bay, Alaska; Flin Flon, Manitoba (Canada) |
| 2b |
-45
to -40 F |
-40.0
to -42.7 C |
Unalakleet,
Alaska; Pinecreek, Minnesota |
| 3a |
-40
to -35 F |
-37.3
to -39.9 C |
International
Falls, Minnesota; St. Michael, Alaska |
| 3b |
-35
to -30 F |
-34.5
to -37.2 C |
Tomahawk,
Wisconsin; Sidney, Montana |
| 4a |
-30
to -25 F |
-31.7
to -34.4 C |
Minneapolis/St.Paul,
Minnesota; Lewistown, Montana |
| 4b |
-25
to -20 F |
-28.9
to -31.6 C |
Northwood,
Iowa; Nebraska |
| 5a |
-20
to -15 F |
-26.2
to -28.8 C |
Des
Moines, Iowa; Illinois |
| 5b |
-15
to -10 F |
-23.4
to -26.1 C |
Columbia,
Missouri; Mansfield, Pennsylvania |
| 6a |
-10
to -5 F |
-20.6
to -23.3 C |
St.
Louis, Missouri; Lebanon, Pennsylvania |
| 6b |
-5
to 0 F |
-17.8
to -20.5 C |
McMinnville,
Tennessee; Branson, Missouri |
| 7a |
0
to 5 F |
-15.0
to -17.7 C |
Oklahoma
City, Oklahoma; South Boston, Virginia |
| 7b |
5
to 10 F |
-12.3
to -14.9 C |
Little
Rock, Arkansas; Griffin, Georgia |
| 8a |
10
to 15 F |
-9.5
to -12.2 C |
Tifton,
Georgia; Dallas, Texas |
| 8b |
15
to 20 F |
-6.7
to -9.4 C |
Austin,
Texas; Gainesville, Florida |
| 9a |
20
to 25 F |
-3.9
to -6.6 C |
Houston,
Texas; St. Augustine, Florida |
| 9b |
25
to 30 F |
-1.2
to -3.8 C |
Brownsville,
Texas; Fort Pierce, Florida |
| 10a |
30
to 35 F |
1.6
to -1.1 C |
Naples,
Florida; Victorville, California |
| 10b |
35
to 40 F |
4.4
to 1.7 C |
Miami,
Florida; Coral Gables, Florida |
| 11 |
above
40 F |
above
4.5 C |
Honolulu,
Hawaii; Mazatlan, Mexico |
http://www.usna.usda.gov/Hardzone/hrdzon3.html
| ZONE
1
| Below
-50F
|
Sow
seed in early spring when soil can be worked
|
| ZONE
2
| -50F
to -40F
|
Sow
seed in early spring when soil can be worked
|
| ZONE
3
| -40F
to -30F
|
Spring:
April 15-June 15
Fall:
August 15-October 1
|
| ZONE
4
| -30F
to -20F
|
Spring:
April 15-June 15
Fall:
September 1-October 15
|
| ZONE
5
| -20F
to -10F
|
Spring:
April 15-June 15
Fall:
September 1-October 15
|
| ZONE
6
| -10F
to 0F
|
Spring:
March 15-May 15
Fall:
September 15-November 1
|
| ZONE
7
| 0F
to 10F
|
Spring:
February 15-April 15
Fall:
September 15-November 15
|
| ZONE
8
| 10F
to 20F
|
Spring:
January 15-March 1
Fall:
October 1-December 1
|
| ZONE
9
| 20F
to 30F
|
Spring:
January 1-March 1
Fall:
October 1-December 1
|
| ZONE
10
| 30F
to 40F
|
Spring:
January 1-March 1
Fall:
October 1-December 1
|
| ZONE
11
| ABOVE
40F
|
Spring:
January 1-March 1
Fall:
October 1-December 1
|
|
