Wednesday, January 25, 2012

New USDA Hardiness Zones Announced


Okay, so most vegetables don't overwinter (asparagus, rhubarb, Jerusalem artichoke and a few others being the exceptions). However, vegetable gardeners are concerned about climate and length of growing season. They are also interested in flowers and herbs for attracting pollinators to the vegetable garden whose persistence may be determined by hardiness zones. Fruit growers certainly have plant hardiness concerns.

What's exciting about the new, online 2012 USDA Hardiness Zone Map announced today? It's been updated to the Internet age with cool, online features. In addition to being able to put in your zip code and automatically get your zone, you can also enter your state name and see how climate works locally.

The coolest feature though is the Interactive Map that shows the streets in your area with the hardiness zones detailed. This is a vast improvement from previous maps where you had to guess your location on an all-to-generalized map. Be sure to click right on the map and use the +/- slide bar to zoom in to your neighborhood.

That said, what has changed with this revision? First, know that plant hardiness zones detail the average annual extreme minimum temperatures at a location for a given time period. In this revision that is the 30-year period from 1976-2005. These zones don't reflect historic lows that occurred before then or might occur in the future.

Compared to the previous 1990 map, the update shows most areas are a half-zone warmer (5 degrees F). In fact two new zones have been added to the U.S., 12 and 13. Each zone is a 10 degree F band that is subdivided into a and b. Most of the Front Range is now 5b with some 6a.