| USDA
Zone |
Temperature
Range |
Example Cities |
When to Plant Outside |
|
1 |
Below
-50 F
(below
-45.6C)
|
Fairbanks,
Alaska
Resolute,
Northwest Territories (Canada) |
N/A |
|
2 |
-50
to -45 F
(-42.8
to -45.5 C)
|
Prudhoe
Bay, Alaska
Flin Flon, Manitoba (Canada) |
Outside Mid-June |
|
3 |
-40
to -35 F
(-37.3
to -39.9 C)
|
International
Falls, Minnesota
St. Michael, Alaska, Tomahawk,
Wisconsin, Sidney, Montana |
Outside Mid-Late May |
|
4 |
-25
to -20 F
(-28.9
to -31.6 C)
|
Minneapolis/St.Paul,
Minnesota; Northwood,
Iowa
Nebraska |
Outside May 1 |
|
5 |
-20
to -15 F
(-26.2
to -28.8 C)
|
Des
Moines, Iowa; Columbus, Ohio; Indianapolis, Indiana
Illinois |
Outside April 15 |
|
6 |
-10
to -5 F
(-20.6
to -23.3 C)
|
St. Louis, Missouri; Lebanon,
Pennsylvania; Newark, New Jersey |
Outside April 1 |
|
7 |
0
to 5 F
(-15.0
to -17.7 C)
|
Oklahoma
City, Oklahoma
South
Boston, Virginia |
Outside March 15 |
|
8 |
10
to 15 F
(-9.5
to -12.2 C)
|
Tifton,
Georgia
Dallas,
Texas |
Outside March 15 |
|
9 |
20
to 25 F
(-3.9
to -6.6 C)
|
Houston,
Texas
St.
Augustine, Florida |
Outside March 1 |
|
10 |
30
to 35 F
(1.6
to -1.1 C)
|
Naples,
Florida
Barstow,
California |
Outside Feb 15 |
|
11 |
above
40 F
(above
4.5 C)
|
Honolulu,
Hawaii
Mazatlan,
Mexico |
Outside Anytime |
