MINOH, Japan — Strawberry shortcake. Strawberry mochi. Strawberries à la mode.
These may sound like summer treats. But in Japan, the strawberry harvest peaks in the winter—a cold season of perfect fruit, the purest of which sell for hundreds of dollars a piece to give as special gifts.
Japanese strawberries have an environmental tax. To recreate an artificial spring during the winter months, farmers grow their off-season delicacies in huge greenhouses heated by giant gas heaters.
“We’ve gotten to the point where many people think it’s natural to have strawberries in the winter,” said Satoko Yoshimura, a strawberry farmer in Minoha, near Osaka, Japan, who until last season burned kerosene to heat her greenhouse all winter. when temperatures can drop well below freezing.
But as she continued to fill the tank of her heater with fuel, she said and began to think, “What are we doing?”
Of course, fruits and vegetables are grown in greenhouses all over the world. However, the Japanese strawberry industry has taken this to such an extreme that most farmers have stopped growing strawberries during the much less lucrative warmer months, the actual growing season. Instead, Japan imports much of its strawberry supply in the summer.
It’s an example of how modern expectations of fresh produce year-round can require surprising amounts of energy, contributing to climate warming in exchange for strawberries (or tomatoes, or cucumbers) even as temperatures drop.
Just a few decades ago, the Japanese strawberry season started in spring and lasted until early summer. However, the Japanese market traditionally places a high value on first-season or “hatsumono” products, from tuna on rice and tea. A crop claiming the mantle of hatsumono can fetch many times normal prices and even garner frenzied media coverage.
As the country’s consumer economy took off, the hatsumono race spilled over into strawberries. Farms began competing to get their strawberries to market earlier and earlier in the year. “The peak strawberry season was from April to March to February to January and finally came to Christmas,” said Daisuke Miyazaki, managing director of Tokyo-based strawberry consultancy Ichigo Tech.
Now, strawberries are a staple of Christmas in Japan, adorning Christmas cakes sold across the country throughout December. Some farmers started shipping the first strawberries in November, Mr. Miyazaki said. (One perfect Japanese strawberry, Oishii (meaning “delicious”), recently became famous on TikTok, but it’s grown by an American company in New Jersey.)
Japan’s shift toward growing strawberries in freezing weather has greatly increased the energy demands of strawberry growing. According to analyzes of greenhouse gas emissions In relation to various products in Japan, the carbon footprint of strawberries is about eight times that of grapes and more than ten times that of tangerines.
“It’s all about heating,” said Naoki Yoshikawa, an environmental science researcher at the University of Shiga Prefecture in western Japan who led the study of production emissions. “And we looked at all aspects, including transport or what it takes to make fertilizer – even then heating had the biggest footprint.”
Examples like these complicate the idea of eating local, namely the idea embraced by some environmentally conscious shoppers of buying food that was produced relatively close, in part to reduce the fuel and pollution associated with shipping.
But in general, transporting food has less of an impact on the climate than how it’s produced, said Shelie Miller, a professor at the University of Michigan who focuses on climate, food and sustainability. For example, one study found that tomatoes grown locally in heated greenhouses in Britain had a higher carbon footprint compared to tomatoes grown in Spain (outdoors and in season) and supplied to UK supermarkets.
Climate-controlled greenhouses can have advantages: They can require less land and less pesticide use, and can produce higher yields. But the bottom line, according to Professor Miller, is that “it’s ideal to be able to eat both in season and locally, so your food is produced without adding a lot of energy expenditure.”
In Japan, the energy needed to grow strawberries in winter has not proven to be a mere climate burden. Growing strawberries has also become more expensive, especially as fuel costs have increased, hurting farmers’ bottom lines.
Research and development of berry varieties, as well as sophisticated branding, have helped alleviate some of these pressures by helping farmers achieve higher prices. Strawberry varieties are sold in Japan with whimsical names such as Beni Hoppe (“red cheeks”), Koinoka (“scent of love”), Bijin Hime (“beautiful princess.”) Along with other expensive fruits such as watermelons, they are often given as gift items.
Tochigi, a prefecture north of Tokyo that produces more strawberries than any other in Japan, is working to address both climate and price issues with a new strawberry variety it calls Tochiaika, a shortened version of the phrase “Tochigi’s beloved fruit. “
Seven years in development by agricultural researchers at Tochigi’s Strawberry Research Institute, the new variety is larger, more disease-resistant and produces a higher yield from the same inputs, making them more energy efficient to grow.
Tochiaika strawberries also have a firmer skin, reducing the number of strawberries that are damaged during shipping. reducing food wastewhich also has climate consequences. In the United States, where strawberries are grown mostly in the warmer climates of California and Florida, buyers throw away an estimated one-third of the crop, partly because of how fragile they are.
And instead of heaters, some farmers in Tochigi use something called a “water curtain,” a trickle of water that surrounds the greenhouses and keeps the temperature inside constant, though it requires access to plenty of groundwater. “Farmers can save on fuel costs and help fight global warming,” said Takayuki Matsumoto, a member of the team that helped develop the Tochiaika strawberry. “That’s ideal.
Further efforts await us. Researchers in the northeastern city of Sendai have been investigating ways to use solar energy to maintain the temperature inside strawberry greenhouses.
Ms. Yoshimura, a strawberry farmer in Minoh, worked in agriculture for ten years before deciding that she wanted to do away with her giant industrial heater in the winter of 2021.
The young mother of one, with another on the way, has spent most of her days reading about climate change during the pandemic. A series of devastating floods in 2018 that destroyed a patch of paradise on the farm she runs with her husband also awakened her to the dangers of global warming. “I realized I had to change the way I farm for the sake of my children,” she said.
But in mountainous Minoh, temperatures can drop as low as 20 degrees Fahrenheit, or about minus 7 degrees Celsius, levels at which strawberry plants would normally go dormant. So she dove into agricultural studies to try to find another way to send her strawberries outside during the lucrative winter months while not using fossil fuel heating.
She read that strawberries sense temperature through a part of the plant known as the corolla, or short, thickened stem at the base of the plant. If she could use groundwater, which is generally at a constant temperature, to protect the crown from freezing, she would not have to rely on industrial heating, she reasoned.
Mrs. Yoshimura equipped her strawberry beds with a simple irrigation system. She covered her strawberries with plastic for extra insulation at night.
She emphasizes that her cultivation methods are in development. But after her berries survived the cold weather in December, she took her industrial heater, which had been left on standby in one corner of her greenhouse, and sold it.
She is now working to gain local recognition for her “non-warm” strawberries. “It would be nice,” she said, “if we could do strawberries when it’s natural.”