Planting Zones in the USA are slowly moving North, warming the Northern Latitudes as Global Warming shows its effect!

Growing Zone Maps of all types are available and deciphering the gardening zones can be confusing, even misleading. Gardening Zone location, though, is information that you must know before you order your herb seeds or potted herbs and before any herb gardening begins. You should try to thoroughly understand the planting zone in which you live and will garden. Know your growing zone by heart.

The USDA Planting zones Map is the standard on which most plant growing zones maps are based.

Be patent and study it carefully. As confusing as it seems to be, familiarity with the planting zones map will pay big dividends at harvest. It has always been and still remains an invaluable herb growing tool.

Gardening Zones map of the United States Mainland

United States of America Mainland

United States Growing Zones by USDA Region

The USDA Plant Maturity Zone Map enjoys wide-spread use

In the eastern half of the country, the USDA Planting Zones Map is the standard against which all other planning zones maps are judged. The area is comparatively flat, so mapping is a matter of mapping lines moving north, in 5 degree increments, approximately parallel to the Gulf Coast. The lines tilt northeast approaching the east coast until they cross the Eastern mountain ranges where the varying altitudes cause greater variations in planting zones.

The Planting Zones Map is less than desirable in the Western US, west of a north/south line which runs roughly through the middle of North and South Dakota and down through Texas west of Laredo. Many factors other than the winter low temperatures, on which the USDA map is based, determine western growing climates. Weather from the Pacific Ocean becomes more continental as it moves east, over and around the Western mountain ranges. The criteria that define the different western zones are completely different and more complicated than in the Eastern US.

Herb seed catalogs and garden nurseries generally use a form of their own gardening zones map.

Most are based on the standard USDA Plant Maturity Zone map. In an effort by the suppliers to simplify the process for you, each may vary slightly due to the interpretations shown in their seed catalog. Just be aware on which information the growing zone map you are viewing is based. Make your buying decision based on each individual supplier's recommendation indicated on their own growing zone map.

Sunset Western Garden Book is the standard among gardeners who live in the 13 western states.

The Sunset Western Growing Zone Map recognizes the difference between garden climates in the east and west by dividing the US into 45 garden zones. Sunset Zones 1 through 24 are west of the 100th meridian, and zones 25 through 45 are east of it.

This system acknowledges the complex gardening regions of the west and recognizes that in many cases neither minimum nor maximum temperatures determine a plant's survival.

Sunset's Gardening Zones are based on regions where particular plants flourish, not on regions that share a feature such as temperature or heat. Instead of matching a plant to an established zone, the zone is created to match the plants!

The USDA Planting Zone Map, whether you live in the Eastern or Western United States, is still the guideline used by most garden catalogs, Internet garden suppliers and direct mail herb suppliers. A herb gardener must be aware that growing zones indicated by one garden supplier may differ slightly from the gardening zones presented by another. Both, though, are doing their best with the information they have. In general, asking questions and paying attention is the best rule when deciding which planting zones map you will use.