In May of 2001, Boston Red Sox coach John Cumberland planted beefsteak tomato plants in the team’s bullpen — 18 of them, to represent the last time that the team had won the World Series in 1918.

“I’m trying to change the karma,” Cumberland, the bullpen coach, told the Boston Herald. “There’s been bad soil here. Hopefully now it’s good soil.”

Cumberland’s tomato plants no longer grace Fenway’s bullpen (though the team finally got their World Series win in 2004), but in the fifteen years since beefsteak tomatoes took root in America’s oldest ballpark, the idea of growing food in a baseball stadium has transitioned from a whimsical attempt at disrupting bad karma to a growing trend embraced by teams across the country. Today, five major league teams have installed urban farms and gardens within their baseball stadiums — and those involved with the projects say that the fans are eating it up.

“The reaction is incredibly positive,” Jessie Banhazl, founder Green City Growers, told ThinkProgress. “People are really excited to see this particular area of the park that was not being used for anything all of the sudden being a thriving farm.”

At the beginning of the 2015 season, Fenway opened a 5,000-square foot rooftop farm along a previously unused stretch of roof behind Gate A, dubbing the area “Fenway Farms.” The impetus for the farm came from Linda Pizzuti Henry, wife of Red Sox co-owner John Henry. Linda had long been interested in figuring out a way to bring a focus on sustainability and healthy eating to the ballpark, and in the summer of 2014, Linda serendipitously crossed paths with Green City Growers, a Boston-based company that had been awarded a Social Impact Prize from Henry’s foundation for its work in creating urban garden and farms.

Banhazl and her colleagues at Green City Growers pitched Linda their idea of creating an urban farm within the walls of Fenway Park. To their surprise, the park had already been considering the idea, looking for ways to turn the vacant space of roof behind Gate A into either a green roof or a garden.

“We were very lucky to have been picked to be the Red Sox’s other farm team,” Banhazl said with a laugh.

For those that only associate baseball farms with farm teams and think of baseball food as consisting of two food groups (hot dogs and beer, or peanuts and cracker jacks), the ballpark might seem like a strange breeding ground for hyper-local, sustainable urban agriculture. But sports fans, it turns out, are beginning to think more about the environmental footprint of their sports experience. According to a poll conducted by Green Sports Alliance, a Portland-based arm of the Natural Resources Defense Council that helps sports teams adopt best environmental practices, 81 percent of sports fans express concern about the environment. The poll also found that 58 percent expect their favorite team to be leaders when it comes to environmental action. There are a lot of ways a sports team can integrate environmental issues into their day-to-day operations, from building LEED-certified stadiums to developing a robust recycling program. But few measures offer such an advantageous blend of fan interaction, consumer education, and marketplace profit like revamping the stadium’s food scene.

“Sports brings people together like no other institution,” Alice Henly, a resource specialist with Green Sports Alliance, told ThinkProgress. “It is a tremendous role model at the center of American culture, but also this powerful force in the marketplace. The overlap of more sustainable food options and the evolution of consumer interest is a tremendous business opportunity for the sports industry.”

Growing vegetables in a ballpark isn’t necessarily a new trend. Before Cumberland tried to “reverse the curse” with some beefsteaks at Fenway, the Mets, the Braves, and the Tigers all reportedly grew some kind of greenery in their bullpens, whether it be tomatoes, corn, or sunflowers.

But integrating the gardens with an eye toward improving a park’s sustainability is a relatively recent movement. There’s a bit of debate about which team created the first edible Major League garden, but the title is most often given to Petco Park — home of the San Diego Padres. In the spring of 2011, Luke Yoder, the park’s director of field operations, planted an assortment of hot peppers and tomatoes. Today, Yoder grows a mix of produce depending on the season — from avocados to blueberries — and the goods are incorporated into a few food items sold around the ballpark, appearing in salsas, relishes, and more.

A season later, two more baseball parks opened their own gardens. The first was at Coors Field in Denver, where Colorado State University teamed up with the Rockies to create the GaRden, a network of raised beds filled with organic soil and watered from drip lines made from recycled material. At 600 square feet, it was, for a time, the largest on-site garden in baseball.

But not for long. In July of 2013, during a White House visit to celebrate their 2012 World Series Victory, the San Francisco Giants announced their plans to turn the centerfield bleachers in AT&T Park into the largest on-site edible garden at a major sports venue.

“With rows of kale and strawberries and eggplant, the Giants are going to help encourage local youth to eat healthy — even at the ballpark,” President Obama said during the announcement.

Shana Daum, vice president of public affairs and community relations with the Giants, says that from the start, the thing that set the Garden at AT&T Park apart from other ballpark gardens was its scope — both its size, and its integration into the overall game experience.

“Other parks before us, it was more of a garden that you passed by and could walk by, but it wasn’t interactive,” Daum told ThinkProgress. “We thought that we could bring community groups of children here to learn about how you can live in the middle of the city and you can grow a garden.”

AT&T worked with Blasen Landscape Architecture and EDG Architects to re-imagine the center field bleachers into an edenic escape for baseball fans. Together, they built raised beds and aeroponic growing towers, and fertilizing the soil with leftover coffee grounds from Peet’s Coffee. When it was initially envisioned, the garden was to span 3,000 square feet and be totally organic, replete with kale and strawberries that would eventually find their way into the stadium’s concessions.

When it opened in June of 2014, the space — dubbed the Garden at AT&T Park — covered 4,320 square feet. In addition to produce, the Garden houses a bar, tables, benches, a fire pit, and two concession stands that serve food prominently featuring Garden-grown ingredients. Produce-wise, the Garden grows everything you’d expect to find in a backyard garden patch (lettuce, tomatoes, zucchini) and a few things you wouldn’t (passion fruit, lemongrass, hops). When it opened, Giant’s right fielder Hunter Pence — a self-proclaimed health nut — was on site to christen the Garden.

“If you want to inspire kids to eat healthy,” Pence said, “you have got to eat healthy yourself.”

And so the Garden at AT&T Park was the largest edible garden at a baseball stadium, until the next baseball season, when all 5,000 square feet of Fenway Farms took root in the Boston landmark. Because Fenway is the oldest baseball stadium in the country, and included in the National Register of Historic Places, it took especially careful planning to create Fenway Farms. The Red Sox consulted with architects and structural engineers to make sure that the chosen section of roof support the weight of a farm, worked with a company that specializes in building green structures on rooftops, and brought in Green City Growers to plant, maintain, and harvest the crops.

All told, the Red Sox had to get approval from five different government agencies at the city, state, and federal level before the farm could become a reality. The Red Sox also installed a smart irrigation system for the garden, which senses weather and moisture in the air and tailors the irrigation to current conditions. Combined with a milk-crate planting system, that Banhazl describes as “totally modular,” the farm is expected to produce some 4,000 pounds of food a year. An added advantage is the farm removes some rainwater that falls on the stadium’s roof, meaning less water flows into the drainage system — a benefit of green roofs in general.

But even with thousands of square feet dedicated to on-site food production, these urban farms are only able to produce a small fraction of the food served at the stadiums. In San Francisco, the produce from the garden is used exclusively at the two concession stands located next to the growing area. At Fenway, the produce from the farm is used only in the EMC Club Dining area, the park’s smallest volume food operation. In the grand scheme of all the food that comes in and out of a ballpark, creating produce for a handful of operations, especially those only available to a select number of ticket holders, can come off as trivial at best and elitist at worst.

Which is partly why these baseball gardens aren’t simply interested in feeding their fans — they’re also trying to educate them.

A month into the Garden at AT&T Park’s existence, the Giants decided to create a position dedicated to bringing the garden to the fans — a sort of liaison between baseball and farming. To Hannah Schmunk, who had been working for the park’s food service partner Bon Appetit in another role, it sounded like a perfect opportunity.

“I heard about the Garden at AT&T Park about a month after it opened, and I thought it was the coolest thing that I’d heard in a long time,” she told ThinkProgress. In September, Schmunk stepped into the role of community development manager, charged with designing the way the space is used on game days, developing tour programs for the space, and running the Garden’s kids program.

The Garden hosts tours of children almost weekly, with 20 to 25 kids involved in each field trip. When the kids first arrive at the Garden, Schmunk gives them an activity that allows them to explore the space — a scavenger hunt, some leisurely harvesting, or planting. Then, they move into cooking activities that incorporate taking the produce from the garden and turning it into a healthy meal. To the children, who Schmunk notes view many Giants players as real-life heroes, learning about healthy eating and agriculture in the same space that their favorite players play makes for an instant connection.

“What I’ve seen in our kids programs that has been so magical is really how the garden comes alive for the kids,” Schmunk said. “They haven’t spent much time in gardens or farms, and they’ve grown up in the inner city. To watch how much joy it brings to harvest a carrot and they can’t believe their eyes that it would come from under the soil … has been truly magical.”

But it’s not just the youngest fans that are subconsciously exposed to the benefits of sustainable food when they come to the Garden.

“I think the biggest impact … that we have is that the ballpark seats 41,500 people on a given night, and this is a garden that is highly visible,” Schmunk said. “We’ve become so disconnected from our food, and the story behind it, and where it comes from. Because our garden is public and open to anyone that comes to a Giants game … we’re able to reconnect and reestablish the connection between people and their food.”

Fenway has seen similar interest from fans since the debut of their farm. The ballpark has always been a popular location, with locals and tourists alike, and hosts tours on a nearly 365-day-a-year basis; due to demand, the farm was added to the stadium tour this year.

“There has been a lot of great interest, and most importantly for us there has been a lot of great interest from students and young people,” Chris Knight, manager of facilities services and planning for the Red Sox, told ThinkProgress.

This season, the Red Sox have hosted a few different school groups, but like San Francisco, they’re hoping to implement a full community program, complete with education outreach. But Banhazl hopes that the movement toward sustainable food and education programs in ballparks doesn’t stop at Fenway.

“All it takes is a little bit of space and a commitment from the park,” Banhzal said. “I don’t see why this couldn’t be done at every ballpark around the country.”

Other ballparks already appear to be taking a cue from Petco, Coors, AT&T, and Fenway — in early June, the Washington Nationals announced that they were converting a portion of their D.C. park into a rooftop garden that would house 180 plants, from zucchinis to herbs. The garden will use compost made of food waste from the park, and the vegetables and herbs will be incorporated into food served in club-level concessions throughout the park. The team told WTOP Washington that, if all goes well, they hope to expand the garden to other parts of the stadium.

To Alice Henly, the five baseball parks that currently boast onsite gardens are just the first wave in an inevitable trend towards an increased emphasis on sustainability at sports venues.

“These practices are an entryway to so many environmental issues, from water scarcity to agriculture and chemical impacts on our land,” she said.

Gardens are a particularly hot trend, she notes, because they enhance the visitor experience — allowing fans to sit among flowers and bumblebees while they enjoy their game — but they also provide an important bridge between two worlds that might, at first glance, seem unrelated.

“It really connects these teams with their communities, and reinforces their commitment to these hugely important issues,” Henly said. “The food that is served at venues, to millions of fans, is a way for iconic sports teams to teach their communities about where their food is coming from, and why that’s important for the health or their communities, each individual fan, and the health of our agricultural system as a whole.”