Unconventional Gardening
Zoning Out
It’s always something. It could be flea beetles on the broccoli. Or blossom end rot on the tomatoes. Or powdery mildew blanketing the pumpkin patch. (Or all of the above!) Gardeners have long taken these — and plenty of other — challenges in stride. But, with increased temperatures and more frequent and extreme weather events, gardeners everywhere are facing some altogether new challenges.
Even the tried-and-true U.S. Department of Agriculture’s Plant Hardiness Zone map has gotten out of whack. After examining data from 5,000 National Climatic Data Center cooperative stations throughout the U.S., the Arbor Day Foundation released a new Plant Zone Hardiness map in 2015. Originally based on the USDA’s 1990 Plant Hardiness Zone map, the new version revealed that many of the country’s climate zones have moved.
Of course, some shifting over a period of decades isn’t unusual. But as for these changes? “It’s very difficult for farmers to react to climate right now, because the pace that it is happening is so much faster than what people had anticipated; it’s happening really quickly,” says Fan-Li Chou. Chou is vice president of scientific affairs and policy for the American Seed Trade Association, which includes conventional GM seed purveyors, as well as organic, conservation and wildflower seed companies, among others.
And, ready or not, growing conditions are expected to continue to change. “As far as temperatures go, over the shorter term — say the next 20 or 30 years — the
scientific consensus … is that the average temperatures are going to continue to rise,” says David Hollinger, director of the USDA’s Northeast Regional Climate Hub.
What’s more, Hollinger notes, “In a lot of places over the last few years, warmer wintertime temperatures and very early springs are causing plants to start breaking dormancy early. But the timing of the freezes and the cold snaps hasn’t changed as much, so you are having plants becoming more vulnerable and getting damaged by the normal springtime cold or frost, because they’re losing that dormancy.”
Location, Location, Location
No matter where you garden, you already may have noticed some crops are trickier to grow than they used to be. “This whole thing is pretty complex, because climate change has different effects in different regions,” says Jim Myers, a professor of vegetable breeding and genetics at Oregon State University. “It might be a longer season or higher temperatures or more extremes — more rainfall or humongous storms in certain areas. Those require different adaptations in different crops.”
According to climate scientist Richard Seager, a Palisades Geophysical Institute/Lamont research professor at Columbia University, the West Coast’s historically warm, dry Mediterranean climate is heading northward. The east coast’s subtropical climate is also shifting north of the coast. “The more subarctic climates in eastern Canada are moving northward as well,” Seager says.
“There are also going to be shifts in precipitation,” he says. “Much of the United States is projected to receive more precipitation with the exception of the Southwest, which is expected to get drier. So, wherever your garden is, you can be thinking about plants that [do] better in a warmer climate. If you are in New Jersey, you might think the plants that will be growing well there in the coming decade or two might be ones that currently are more suited to growing in Virginia, for example.”
New Seed Solutions
Plant breeders are combining new technologies with time-tested practices to develop staple crop varieties that can better withstand the current — and continued — climate changes. “What the breeders are trying to catch up with is, ‘How do you develop a new variety that can be grown where you’ve always grown it — even under new climate conditions?’” Chou says. “There are a lot of people working on drought-resistant wheat and droughtresistant rice, because those are the major food crops. But I think fruits and vegetables are much harder. In the U.S. right now, many of the plant breeders are working on how to grow more vegetables [that require] less water.”