Hardiness Zone Maps, and Their Shifting Zip Codes

<a href="https://planthardiness.ars.usda.gov/" rel="noopener ugc nofollow" target="_blank">Plant hardiness zones</a> are categories created <a href="https://en.wikipedia.org/wiki/Hardiness_zone#:~:text=The%20original%20and%20most%20widely,average%20annual%20extreme%20minimum%20temperatures." rel="noopener ugc nofollow" target="_blank">by the USDA</a> to help people understand which plants are likely to thrive in certain environments. It’s a system calculated from the <a href="https://www.climatehubs.usda.gov/sites/default/files/Cold%20Hardiness%20Ag%20FS%20_%20120620.pdf" rel="noopener ugc nofollow" target="_blank">coldest temperature of the year</a> at each location, averaged over a 30-year period. Hardiness — in this context — refers to the likelihood of a plant dying from the cold. I’m writing about this because, apparently, plant zones borders have <a href="https://noaa.maps.arcgis.com/apps/MapSeries/index.html?appid=5f617f338eb5431eb3700e8685eccaf7" rel="noopener ugc nofollow" target="_blank">moving upward over the past few decades</a>. The NYTimes <a href="https://www.nytimes.com/interactive/2019/05/23/climate/plant-hardiness-zones-shifting.html" rel="noopener ugc nofollow" target="_blank">has a more comprehensive piece</a> on this than I do, so I would recommend reading their page if you want to get full story; they ask a few growers in the piece how their gardening habits have changed, and it’s nice to hear from the practitioners themselves about the problem. <a href="https://medium.com/@juweek/hardiness-zone-maps-and-their-shifting-zip-codes-b1dd2a1eada2">Visit Now</a>