The USDA just came out with all new maps for US Plant Hardiness Zones. The best change is how easy the maps are to read. They're designed for the web and they look great. They're also the culmination of 30 years of data and should be more accurate. Thankfully there's still a zip code look up, for those of us who want to cut to the chase. Don't worry, your existing plants won't now they've moved a zone or 2. They'll still be fine. Here's a look at the changes made to the USDA Plant Hardiness Zone Maps. Then go to the USDA site and find your new zone.
Photo: USDA Plant Hardiness Zone Map, 2012. Agricultural Research Service, U.S. Department of Agriculture. Accessed from http://planthardiness.ars.usda.gov/.
Comments
I did not see anything at all wrong with the old one. it was fine. I think some people have too much time on their hands that they have to keep constantly changing things needlessly. I use this:
Minimum annual temperature:
Zone 1: below -46 C (below -50 F)
Zone 2: -46 to -40 C (-50 to -40 F)
Zone 3: -40 to -34 C (-40 to -30 F)
Zone 4: -34 to -29 C (-30 to -20 F)
Zone 5: -29 to -23 C (-20 to -10 F)
Zone 6: -23 to -18 C (-10 to 0 F) Lancaster, PA.
Zone 6a= -10 to -5 F
Zone 6b= -5 to 0 F
Zone 7: -18 to -12 C (0 to 10 F)
Zone 8: -12 to -7 C (10 to 20 F)
Zone 9: -7 to -1 C (20 to 30 F)
Zone 10: -1 to 4 C (30 to 40 F)
Zone 11: above 4 C (above 40 F)
http://www.usna.usda.gov/Hardzone/ushzmap.html
http://www.backyardgardener.com/zone/index.html
Convert Celsius to Fahrenheit= http://www.mathsisfun.com/temperature-conversion.html
I don’t think the new zones are going to make a big difference to the average gardener. But I’m hoping the more detailed calculations will make labeling plants more accurate. I’ve bought too many plants labeled for my zone that couldn’t handle winter.
BTW, there’s a zip code zone finder on this site, too.
i follow the tables as well as i can, but we live in a frost pocket. it frosts on us when no one around us has a problem. we have the last frost in the spring and the first one in the fall. so if we try to grow something not quite recommended for our zone, we are always out on those questionable evenings covering tender plants. its a crap shoot, but we perservere and hope for the best. or, hope next year is better, lol!
I just checked and they “warmed up” my zone to “5A” or -20. Yet we reach -30 most winters at least a time or two. I’ll still opt for zone 4 hardiness and ignor these new guidelines. I have lost too many plants.