The 2012 USDA plant hardiness zone map has been released. The niftiest thing about this latest release is the interactive online aspect.
The USDA plant hardiness zone map shows the average lowest temperature in an area over time and is mainly used by gardeners and growers to determine which plants will be able to survive a winter. It’s also used to set crop insurance standards and model the spread of exotic weeds and insects.
Zones have shifted north a little due to warmer average annual temperatures. Two zones have also been added on the warmer end of the scale – 12 and 13, both of which occur only in Hawaii and Puerto Rico.
Making the 2012 USDA Plant Hardiness Zone Map
The USDA used a more sophisticated algorithm to produce the 2012 plant hardiness zone map than they used in the 1990 map. The algorithm interpolated zone boundaries between weather station readings by taking into account changes in elevation, proximity to large bodies of water, and positionon the terrain, such as valley bottoms and ridge tops.
In addition, information from the years 1976-2005 – a thirty-year time span – went into the calculations. The 1990 map used only the years 1974-1986. Data from more weather stations was also used.
Using the 2012 Map
The USDA has no plans to publish any posters of the new map, like they have in previous years. The map is freely available on their web site.
Users can print out as many copies as they want on their own printers.
To find your plant hardiness zone, enter your zip code in the box on the upper left. Immediately underneath the zip code, you’ll see your zone in blue letters.
The map itself is clickable. Click on your state to open up a static version of the map and print that off for your own use.
2012 USDA plant hardiness zone map, courtesy of USDA