The ‘New Normal’ of Climate Change Means Changes for Your Garden
I grow a type of pea called Wando in my Los Angeles backyard. While I love a good, weird plant name, the choice isn’t based totally on diction but rather on climate: Wando, unlike many shelling peas, can handle heat in a way cool-weather crops, for the most part, cannot. With the temperature set to hit record highs this weekend, climbing above 90 degrees, I’m less worried about the just-flowering peas than I am my fava beans and cabbage, which may wither in the heat.
Planning a garden—what to plant when and what to plant where—can make you think about weather and climate on a more incremental scale. Whereas a late spring freeze (or, in Southern California, an early heat wave) means a change of wardrobe for you, it could decimate parts of your garden. One way of coping with the sensitivity of crops is to follow the USDA plant hardiness zone map. Based on extreme low temperatures, the zones (I’m in 10a) help gardeners pick plants that are best suited for the climate they live in. While it would seem to be a static designation, you don’t have to move to find your garden in a new zone—climate change can take care of that for you.
A new map published Monday by the National Oceanic and Atmospheric Administration shows the northward drift of more temperate growing zones, areas where the average winter lows are getting higher. The 10-degree planting zones depicted in the interactive map show the U.S. Climate Normals—30-year weather data averages that are updated every decade—for 1971 to 2000 and 1981 to 2010. The last update was made in 2011, and considering that 2014 was the warmest year on record globally, people in border regions may already be able to grow plants only suitable for the zone immediately to the south.
The creep of zone 6 from central Missouri into the southeastern tip of Iowa, not far from where I grew up, could change the way my dad goes around gardening, but this is about more than just backyard crops. “Not only can plants generally survive farther north than they used to,” the accompanying post from NOAA reads, “but the fire season is longer, and pests are able to thrive and spread in forests and other natural landscapes. Pollination patterns may also be changing.”
With much of the country coming off a brutal winter, the notion that winter lows are climbing may be hard to reconcile for people living just about anywhere other than Southern California. My fava beans, however, would beg to differ. I hope they survive the weekend.