what zone are you? a new usda hardiness map

HALF THE NATION’S 80 million gardeners will find themselves officially declared a half-zone warmer today, when the United States Department of Agriculture launches the first update since 1990 to its Plant Hardiness Zone Map. No, the new map is not technically a confirmation of a trend toward global warming, the agency says—a different set of data is used in it than in those longer-range calculations—but it is a more accurate picture of growing conditions across America, particularly in tricky areas such as mountainous ones that may have been rated too cold or too warm in previous versions. We have ever-more sophisticated computers to thank for enabling scientists to capture the more accurate take on things.

“The increase in our computing power today allows the research team to build into their algorithms things they knew were important factors in 1990, but couldn’t include,” said Catherine Woteki, Chief Scientist and Under Secretary for Research, Education and Economics for the USDA, in an interview yesterday. Factors such as elevation, the slope of land, or how close to a body of water a location is, can cause sharp variation despite close adjacencies.

“Taking those into account now provides a lot more detail,” Woteki said, “and people will be able to see islands of heat, and also cool ones, on the new map. As a scientist and a home gardener, I love seeing this so much more clearly.”

The new map is built using digital Geographic Information System technology and you’ll notice the sharper boundaries and better resolution right away when you visit its interactive website. To find out whether your zone has shifted, start here. Though I’ve always thought of myself as a Zone 5B, I’m now officially there, no longer in Zone Read more on awaytogarden.com