After the 2021 “heat dome” and flooding, as well as a hard freeze in winter 2023-24, Whatcom County growers are having to rethink how they farm in response to unexpected and often-devastating weather events.
The Environmental Protection Agency has forecasted climate change will bring new challenges to agriculture, including harsher weather and natural disasters. A recent update to the USDA Plant Hardiness Zone Map, suggests things have already been heating up.
The map gives consumers an idea of what kinds of plants will grow in an area using data from weather stations taken over the last 30 years to create numbered “zones” across the U.S. Zones are geographical areas that have similar minimum winter temperatures on average, which very roughly correlates with an area’s overall climate.
The map, updated in November 2023, shows most of the nation — including much of Northwest Washington — has shifted one zone higher. That is, average minimum winter temperatures in most places have gotten 5-10 degrees Fahrenheit warmer in the last decade. The USDA attributes some of these changes to more sophisticated measurement techniques, but to local growers, the updates reflect what they’ve already known for years — things are changing.
Jason Weston, co-owner of Joe’s Gardens, has been raising vegetables at the same location in Bellingham for more than 40 years. He said the trends in rain and temperatures in recent years are too persistent to be flukes.
“We know weather. You get something weird happen one year, that’s just weather. If it happens two years in a row, that could still be random chance. But you get the same thing happening three years or more, that’s when we know we have to adjust,” Weston said. “[Growing conditions] have changed a tremendous amount in the last 10 to 15 years, and they changed hard. And fast.”
But the changes aren’t purely heat related. Weston said the biggest shifts have had to do with weather patterns, mainly rain coming at unusual times and storms getting heavier and more sporadic. This can make it hard for young seedlings to get their start in spring.
Kayla Garcia, store manager at Boxx Berry Farm outside Ferndale, said the farm’s berries have also suffered from the past few years of weird weather.
“In 2022, we went from it being warm, summer temperatures in the third week of October to then freezing temperatures by the third week of November that year. That’s a really short window,” Garcia said. “It’s really hard on the berries.”
The problems most likely to be felt by local farmers and gardeners are what’s known as “cascading effects”: shifts in the planet’s natural weather patterns and rhythms caused by the slow but steady increase in global temperature. This can lead to erratic rainfall, heavier storms, and faster, more drastic shifts in temperature: bad news for crops.
Chris Benedict, an agriculture professor at Washington State University and regional specialist at the Whatcom County Extension, said that the USDA map updates are a better tool for looking backward rather than forward. That’s because they only take average minimum winter temperatures into account, which don’t tell growers about extreme temperatures their crops might face.
“It’s extremes that are playing out right now. That slow march … toward something like a USDA Hardiness Zone change I think is going to be less influential in the next 20-40 years than the [weather] extremes, which is what a lot of the climate shift is.”
Gardeners felt one of those extremes last winter during a freeze that killed many Whatcom County residents’ beloved plants, some of which have been growing for generations.
“We’ve had people come in and they’re like, ‘I lost the plant that my grandmother grew me.’ I mean they had it for a generation, so that’s always a bummer to see,” said Torrey Fore, garden center manager at Joe’s Gardens.
While losing a plant can be heartbreaking, there are ways gardeners can adapt to the changing climate. Fore suggests integrating native plants into the garden as they are usually locally adapted and more resilient to harsh conditions than exotic varieties.
Many resources for home gardeners besides the USDA Plant Hardiness Zone Map can give more detailed guidance on what to plant where. Benedict points out AgWeatherNet, an online portal where Washington residents can get soil temperatures, humidity, dewpoints and other weather measurements from local stations. The Washington State Extension also offers comprehensive guides on how to garden locally and is prepared to answer questions about how home gardeners can handle erratic and extreme weather.
For farmers, the only thing certain about the future is that things are going to change. To combat the inconsistent rainfall, Weston said Joe’s Gardens is upgrading the farm’s irrigation systems to ensure seedlings have moisture whether nature cooperates or not. The folks at Boxx Berry Farm use drip tape to minimize the amount of water needed during dry periods to nourish their crops.
“It’s not exactly more challenging,” Weston said, looking out toward a field of this spring’s crops, “just different. You can’t get caught up doing what you’ve always done. You’ve got to adapt.”
Ben Long is an environmental/science reporter, placed at CDN through the American Association for the Advancement of Science (AAAS) Mass Media Fellowship. Reach him at benlong@cascadiadaily.com.
