Are You in a New USDA Hardiness Zone?

Image:  USDA-ARS /OSU

Last year, the USDA (U.S. Department of Agriculture) along with the ARS (Agricultural Research Services) and the folks at Ohio State University updated the hardiness zone map. Why? Well, times are changing and so are average minimum temperatures, which happen to be the main factor in determining climate regions.

A Review on USDA Hardiness Zones

To recap, hardiness zones are designated areas where certain plants are suitable for growing. If you’ve ever thumbed through a seed catalog you’ve probably noticed something along the lines of “zones 4-9" under a plant’s description. This tells you that particular plant can handle the average minimum temperature for those hardiness zones, and if you happen to live in one, go ahead and grow it.

Each hardiness zone represents a 10 degree (Fahrenheit) segment. These segments, sometimes called climate regions, extend over several states and provinces. Many states and provinces have more than one hardiness zone, which is why it’s important to consult the USDA hardiness zone map for the climate zone in your area.

The New, Improved USDA Hardiness Zone Map

The new map, updated for the first time in 2012 since 1990, has changed somewhat. Don’t worry, there’s no need to go dig up your perennials and swap out your favorite evergreens for new ones. Perhaps the biggest change are the subsets associated with each hardiness zone. For example, instead of seeing zone 5, you’ll now see zone 5a and 5b.

Why the addition of climate zone subsets? Each subset represents a 5 degree difference in average minimum temperature for that area. Average minimum temperatures are gathered over a period of time so they are more accurate. The USDA hardiness zone map was updated because the earth is warming, changing average minimum temperatures.

Furthermore, internet users are going to find an internet-friendly version of the hardiness zone map online. Each zone is clearly defined on the map; gone are the days where squinting is required to find your climate region on a fuzzy picture. Perhaps one of the best features is the ability to click on a single state and have a large, static map pop up for easier viewing.

Not sure which new hardiness zone you’re in? Simply visit the map, type in your zip code and the map will generate your zone for you. It’s as simple as clicking a few buttons and hitting the enter key.

If you haven’t already, check out the new USDA hardiness zone map and choose your plants accordingly. I don’t think you’ll have to make any significant changes in your gardening. I’ve already started planning my garden and making lists of the vegetables and varieties I want to plant. Have you?

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