Posts Tagged ‘history of plant hardiness zone map’

History of the USDA Plant Hardiness Zone Map

Farmers Great Depression-300x240 in  and gardeningtipsAs gardeners prepare for the upcoming gardening season, many will be viewing incoming seed catalogues along side their morning cup of coffee.  Throughout the catalogue plant hardiness zones will be mentioned but do you really know the history behind these maps?  This tale is full of intrigue, competition, and human nature.

The story begins among one of the darkest moments in United States history and that is the Great Depression.  Two individuals working for two different agencies were honing in on an idea and that was a temperature map that could guide farmers in their plantings.  Before this idea was conceived, plantings were guided by family traditions and The Farmers Almanac.

So during the 1930’s The U.S. National Arboretum was working on a map that would divide the United States into zones that were separated by 10 degrees Fahrenheit.  At the same time, Arnold Arboretum was developing its own map.  This map was divided into eight zones that could have a temperature difference of 5, 10, or 15 degrees.

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