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  • New Plant Hardiness Zone Map

    The USDA released a fancy new version of the Plant Hardiness Zone Map today. For the first time, the map is available as an interactive GIS-based map. I'm curious how much the zones have changed. According to the new map, has your zone changed?

    Check it out...

    http://planthardiness.ars.usda.gov/PHZMWeb/

  • #2
    My neighborhood went from 4a to 4b.

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    • #3
      Mine went from borderline 4b/5a to straight 5a. But then, because I live in a suburban area near a lake system, I always planted as if I was 5a. It's just official now.

      There's a lot being made of this on garden sites, but I haven't noticed a major change in winter low temps. I think the map is just getting more accurate.
      Last edited by WI_HO_C; 05-24-2012, 08:03 AM. Reason: typo

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      • #4
        I as well moved from 4b/5a to 5a, by 30 miles now, yahoo!

        Dean

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        • #5
          The map gives a general guideline, but it can't show the microclimates which can change in very short distances. For instance, in our area of valleys and ridges, we used to garden in a valley bottom that had cold air drainage from a north facing deep ravine. Then we moved up to the ridge, a little over a mile as the crow flies. We get at least a month longer growing season and the nights are almost always warmer which also has a big effect. Our whole area is listed as 4b but the valley performed more like 4a and some years was more like 3b (frost on June 21st and Sept. 6th one year) and hit a low of nearly -40F one year. Bottom line - be aware of the extremely local microclimate!

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          • #6
            I moved to my home 25 years ago and the old-timers then told me we were in zone 4. In fact, the first couple of winters I lived here we saw a week straight of minus 40 degrees. But, the last dozen winters here have not dipped below minus 15, so I guess going a zone up actually does apply to the last dozen winters here. However, I have experienced that the "winter kill" to many of my plants does not come when the weather is minus 15 or even minus 40. The plants are sufficiently dormant at that time. The "winter-kill" will happen in early March here, when the temperatures begin to warm up for spring. We will get a couple weeks of warmer weather, and the plants will start to wake up. But then after their sap gets to flowing, we will then get more subzero temps in March. So, I don't think there might be that much difference between minus 15 and minus 40 when it happens in January, but it sure makes a difference when it happens in March. I don't think the new zone maps take the low March temps into consideration for certain areas.

            I am now in zone 5.

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            • #7
              5b to 6a. Of course that's just a label. My garden is still in the same place and the same temperature it was last year.

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              • #8
                Originally posted by Walk View Post
                The map gives a general guideline, but it can't show the microclimates which can change in very short distances.
                Good point and important to remember!

                According to the FDA website, the new map does take into account some micro climate info, such as elevation:

                "Because this map was created digitally with GIS technology, it has a higher level of resolution and can show smaller areas of zone delineations than ever before. For example, cities tend to hold more heat because they have large amounts of concrete and blacktop, so a city or town may be assigned to a zone warmer than the surrounding countryside. Higher elevations tend to be colder than surrounding lower areas, so the top of a mountain may be an area of cooler zones. A location near a large body of unfrozen water may provide milder winter weather and be in a warmer zone."

                http://planthardiness.ars.usda.gov/P...tWhatsNew.aspx

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                • #9
                  I still think we are going into an ice age,
                  and NASA is starting to agree with me
                  what I have learned from many forums is that not many people know what ice age weather really is

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                  • #10
                    Global Warming? Ice Age?

                    Low Fat? No Carbs? South Beach? Low Glycemic Index? No Red Meat? Atkins?

                    They can't all be right.

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                    • #11
                      Global Warming is just a smokescreen to cover up ongoing weather manipulation experiments. Google "Owning the Weather by 2025" and "Global Dimming."

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                      • #12
                        Whats the difference between an a zone and a b zone?

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                        • #13
                          Originally posted by Arrow View Post
                          Whats the difference between an a zone and a b zone?
                          It's just a finer distinction than going from 7 to 8.

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                          • #14
                            My zone did not change -- still 9b (25-30).

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                            • #15
                              Went from 7b to 8a

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