USDA Hardiness Zones


Zone 1
Minimum temperatures: Below -50F = (Below -46C)

The coldest areas on the North American continent are found in Zone 1, which encompasses the extreme northern parts of Canada; parts of the Yukon Territory, Alberta, and Saskatchewan; the interior of Alaska; and parts of the Aleutians and Kodiak Island. Only the hardiest plants will survive in the extreme winter cold and short growing season of Zone 1.

Zone 2
Minimum temperatures: -50 to -40F = (-46 to -40C)

Zone 2 stretches primarily across most of Northern Canada to Alaska's interior and the Bering Sea; some of the highest mountain areas of Wyoming and Montana also fall into this zone. Although still an area of extremely cold winter temperatures, Zone 2 is modified by the warming influence of large bodies of water. As in Zone 1, the growing season is short.

Zone 3
Minimum temperatures: -40 to -30F = (-40 to -34C)

Zone 3 can be found in Alaska; southern Canada; along Hudson Bay and mainland Newfoundland; in the interior areas of Maine, Vermont, and upstate New York; across the northern Midwest; and into Montana. Some of the highest regions in Wyoming, Utah, and Colorado also fall in this zone. The lower latitudes mean winter is not as cold as in Zones 1 and 2, but frosts can still occur any night of the year and the growing season is short.

Zone 4
Minimum temperatures: -30 to -20F = (-34 to -29C)

Zone 4 generally falls at a more southerly latitude than Zones 1 through 3. Large bodies of water throughout much of this zone also help to create warmer winter temperatures and a longer growing season. Zone 4 gardens exist mostly in a belt across the north central United States from southern Montana to central Wisconsin and into Michigan, and down into the high Rocky Mountain regions of Colorado. It also includes southwest Maine, and most of the northern regions of Vermont, New Hampshire, and New York.

Zone 5
Minimum temperatures: -20 to -10F = (-29 to -23C)

Although gardeners in Zone 5 still experience winter cold, this zone benefits from lower latitudes and an ocean influence. In the eastern United States, it stretches across Newfoundland and Nova Scotia and along the seacoast of Maine and New Hampshire. It continues through western Massachusetts and mid-state New York, northern Pennsylvania, Ohio, Indiana and Illinois, much of Michigan, southern Iowa and Nebraska, northern Missouri and Kansas, and eastern Colorado. In the interior West, this zone forms a patchwork pattern that extends from New Mexico into British Columbia, the southern Alaskan coast, and the Aleutians.

Zone 6
Minimum temperatures:
-10 to 0F = (-23 to -18C)

Zone 6's southern latitude bestows a long growing season and milder climate than Zone 5. It begins along the coasts of Massachusetts, Connecticut, Rhode Island, New York, and northern New Jersey, then extends through southern Pennsylvania and southwest through the country's midsection, to northern Texas. In the West, Zone 6 includes parts of Arizona, New Mexico, Utah, Nevada, Oregon, and Washington, then extends narrowly north along the coast of Alaska. Eastern gardeners contend with humidity, while in the West dry heat and a lack of rainfall are the gardening challenges.

Zone 7
Minimum temperatures:
0 to 10F = (-18 to -12C)

Zone 7 is the middle ground of gardening in the United States. It covers a Southern belt from Delaware into northern Georgia, then continues west into southern Oklahoma and northern Texas. In the East, ocean influences allow Zone 7 to continue north along the New Jersey coast, Long Island, and Cape Cod. Westerly, it snakes through southern New Mexico; bits of Arizona, Nevada and southern Utah; up the eastern border of California, into the central mountainous regions of Oregon and Washington; and into Alaska's Inland Passage. With lower elevations and longer days, many plants thrive in Zone 7.

Zone 8
Minimum temperatures:
10 to 20F = (-12 to -7C)

Zone 8 skirts near the western and southern borders of the United States, from the rainforests of Washington's coast to the coast of North Carolina. Winters here are relatively warm, growing seasons are long, and rhododendrons flourish. In the East, you'll encounter hot, humid summers; in the Northwest, you'll enjoy mild summers with some of the best American gardening climate; and in the Southwest you'll have the definite winters and hot, dry summers of the desert.

Zone 9
Minimum temperatures:
20 to 30F = (-7 to -1C)

One of the smallest regions in the plant hardiness zone map, Zone 9 includes central Florida, the Gulf coast of Louisiana and Texas, much of California, and the southern Oregon coast. This mild-winter region is characterized by a long growing season and almost no winter freeze. Summers are either hot and dry or hot and humid. Although it might seem that just about any plant could do well in such a mild area, Zone 9 (and warmer) is not good for plants that require a winter chill.

Zone 10
Minimum temperatures:
30 to 40F = (-1 to 4C)

Zone 10 is virtually free of winter chill and is dominated by balmy ocean influences. It stretches along parts of the California coast and covers the tip of Florida, into the Florida Keys. Zone 10 can also be found in northern Kauai and the central part of the island of Hawaii. This is the home of subtropical and tropical plants, with a year-long growing season and heat modified by the ocean. Some of our most popular houseplants grow to incredible dimensions outdoors in this zone. It's not real easy to grow apples, but you sure can grow tropical fruits.

Zone 11
Minimum temperatures:
40F and above = (4C and above)

Tropical Zone 11 is found in Hawaii and the lowermost Florida Keys, where oceanic breezes and influences dominate. This is the true tropical paradise zone, with mild temperatures and a growing season that extends year-round. In zone 11, far more gardening dangers exist from tropical storms or the occasional volcano, than from freezing weather.