Elizabeth Makarewicz was up to her elbows in brightly colored peppers of all sizes and shapes. They bobbed in a huge galvanized tub full of water in front of her, getting their final rinse before being sorted and packed for a trip to two farmers markets.

Next to the peppers were buckets, totes, boxes and bags holding all manner of produce from multicolored beets to heirloom tomatoes and sunflower shoots.

Makarewicz was in the “pack room” with a handful of others who work for Stone’s Throw Urban Farm, a small business that grows produce at 16 vacant lots in Minneapolis and St. Paul that have been converted to mini-farms.

The 4-year-old urban farm is still an experiment of sorts, testing whether a commercial farm can make it in the city. Stone’s Throw has been working at it since 2011, when three smaller farms pooled their resources and merged. And it passed a major hurdle this summer by becoming certified as an organic farm — the first urban farm in Minnesota to achieve that status.

The farm hopes the new designation will open up even more markets.

Urban agriculture has always been part of cities, said Julie Dawson, assistant professor of horticulture at the University of Wisconsin-Madison and a specialist in urban and regional food systems.

“What’s fairly new is that there’s more interest and more public recognition that urban agriculture can bring benefits to the city, regardless of whether you’re the one farming or not,” she said.

Those benefits include green space and better aesthetics in communities, she said, and “food sovereignty,” which means options for people in neighborhoods that don’t have grocery stores. “Those are places where people rely on corner stores which can’t necessarily get the best produce because they don’t have enough volume or turnover or cooler space,” Dawson said.

As far as she knows, no one has estimated the number of urban farms in the United States. A handful exist in the Twin Cities, including McKinley Community Urban Farm with seven plots in north Minneapolis and Growing Lots Urban Farm in south Minneapolis. A few others are nonprofit educational farms.

Caroline Devany, one of Stone’s Throw’s five full-time workers, said people walking by her farm’s plots often stop to ask questions or share stories about their grandparents’ gardens. And younger people are especially curious, she said.

“A lot of people don’t know what production agriculture looks like even at our very small scale of an urban lot, and they’re really surprised to see rows of vegetables,” Devany said. “So that feels important.”

Theft occurs but is minimal, she said, because neighbors are proud of the mini-farms and watch over them.

Stone’s Throw leases most of its plots on an annual basis and doesn’t own any land. That’s one challenge of farming in the city, Devany said.

“People are interested in seeing us around but only until building projects are financed,” she said. “So the sustainability of our business depends on trying to figure out the long-term spaces that we’re going to be able to use.”

Another challenge is trying to make a living, said John Seitz, a part-time worker for Stone’s Throw and a full-time butcher at the Wedge Co-op in Minneapolis.

“It’s hard to imagine anyone making a lot of money at this because the margins for food in general are so tight that it almost forces you to become bigger,” he said.

Seitz has been growing food on city lots for several years and jokes that at age 35 he’s the old man of the Stone’s Throw crew.

“I would hope that we could grow our food not just for those willing to pay more for it,” he said. “But it’s hard to balance that because you still have to make money and keep things going.”

One strategy is to grow food intensively on the plots, which combined total about three acres.

Devany said Stone’s Throw grows the equivalent of eight acres of crops on that land by planting two or three successional crops each season when possible, interseeding one crop with another and using high tunnels or hoop houses — essentially greenhouses with walls that can be hiked up — to extend the growing season on both ends.

Another tactic is to focus on higher-value crops, such as culinary herbs, salad greens and heirloom vegetables, and sell them to restaurants and other customers that will pay premium prices.

Those strategies have produced sales that gross about $50,000 per acre, Devany said, five to 10 times more than a typical organic farm outside the city. Although Stone’s Throw only received official organic certification in July, she said, it has always used organic practices that prohibit synthetic fertilizers, herbicides and pesticides.

Devany said the co-op’s plots have also been tested for pollutants and are safe.

The food is sold on Saturday mornings at the Mill City Farmers Market near the Guthrie Theater in downtown Minneapolis and the Midtown Farmers Market near East Lake Street and Hiawatha Avenue.

Stone’s Throw also sells food to more than a dozen restaurants and provides produce for a Community Supported Agriculture (CSA) program, where about 170 subscriber-members pay to receive one box of food weekly between early June and mid-October.

Last year, Stone’s Throw joined four other farms to found Shared Grounds Farmers’ Co-op in order to pool resources, provide more variety to CSA customers and develop new markets. The other farms — three of them managed by Latino growers — cultivate crops outside the city that require more space: melons, squash, tomatoes, Brussels sprouts, cabbage, broccoli and other veggies. Initial funding came from federal grants and technical help from the Minneapolis-based Latino Economic Development Center.

Robin Major, manager of the Shared Grounds, said it has been a fruitful enterprise that takes advantage of fresh salad greens and herbs from Stone’s Throw grown close to city customers and the more distant farms’ needs to connect with urban markets and restaurants that offer higher prices.

“Our goals are definitely to add more beginning and immigrant farm producers that may not have access to the local market,” Major said.

Dawson said an urban farm with some of its crops marketed by a larger producers’ co-op may prove to be a profitable model.

“The current challenge is scaling up local food by increasing the farms that are successful,” she said, and not just because they find high-end markets. “To have a local food supply that really can serve grocery stores and more institutional markets, that’s where the next challenge will be.”