Chef and restaurant owner Cara Stadler is hoping to open an aquaponic greenhouse in a 55-by-60-foot, two-story building that will also house a new café and a commercial kitchen in the fall.

It’s not as if Cara Stadler has nothing to do. The 30-year-old chef already has three restaurants, the newest of which – Lio – opened in Portland just last month.

Now, drivers passing by Tao Yuan in Brunswick are watching the busy chef’s next project come to life before their eyes. Five years in the making, it’s an aquaponic greenhouse in a 55-by-60-foot, two-story building that will also house a new café and a commercial kitchen to supply Stadler’s restaurants. Both Stadler and Kate Holcomb, the 31-year-old project director, say they hope the facility will open this fall.

Chef Cara Stadler, left, and Project Director Kate Holcomb pose inside the aquaponic greenhouse being built in Brunswick.

When it does, it will be just one of a handful of restaurants around the country that have such a facility. Stadler believes her restaurant-based project will be the first of its kind in Maine.

Aquaponics is a marriage of aquaculture and hydroponics, which is the cultivation of plants in water. Aquaponic greenhouses raise fish – in this case rainbow trout – that produce waste that fertilizes plants growing in water. The plants, in turn, filter the water for the fish. It’s a closed-loop system that sustainable agriculture groups are eager to develop.

Most aquaponics projects are either school-based, such as in Maine those at the University of Southern Maine in Gorham and the University of New England in Biddeford, or independent businesses that sell to restaurants and retailers, such as Springworks Farm in Lisbon.

Brian Filipowich, chair of the Aquaponics Association in Annandale, Virginia, said he knows only of a “small handful” of restaurants that are trying aquaponics; he thinks that more restaurants are experimenting with hydroponics. It’s hard to be sure because no good statistics exist on the number of large-scale, commercial aquaponics systems in the United States, say for wholesale or run by restaurants, he said, adding that the Farm Bill just passed by the Senate directs the USDA to start collecting more data on the subject.

Stadler believes her aquaponics facility will bring her food and transportation costs down and will shrink her carbon footprint. She intends to grow, in part, hard-to-source Asian greens and herbs. Eventually she’d like to share what she learns with other restaurateurs.

“This is all very new territory to most of the world,” Stadler said, “and people are still figuring out the systems and what works best, what gives the highest productivity.”

Stadler and Holcomb see the aquaponics greenhouse, which will be called Canopy Farms, as a community project that could become a model for others. It’s a big experiment to discover which equipment will work best and which plants will thrive in Maine, especially over the winter. They want to create something new, helpful, affordable and scalable that would work not just in a rural setting but urban areas too. Something people will actually invest in. Something other restaurants could use to feed their customers.

“This is one of the ways we can help and contribute back to what I find sometimes can be a depressing world,” Stadler said. “Ideally, we can create a system that is positive for us, positive for the future. You realize that, at the end of the day, it doesn’t matter how much you care. If you can’t make systems financially viable, the world won’t care. So we wanted to create a green system that is financially viable.”

Filipowich says if someone like Stadler can overcome the hurdles inherent in such a project – startup and training costs, sourcing fish and maintaining fish health, and energy costs – Canopy Farms could end up making a real contribution.

“If they could get to a point where it could be replicated on a larger scale, it could be extremely useful,” he said.

What about winter?

The cost of heating a greenhouse in winter is a huge obstacle to aquaponics in colder parts of the country, like Maine, Holcomb said.

Kate Holcomb, project director, and Cara Stadler plan to use solar panels, radiant floor heating and an “energy curtain” to offset some of the effects of the long, cold Maine winter on a year-round greenhouse operation. If they can raise the money, they also hope to recapture heat from the commercial kitchen and use it to heat the greenhouse.

“Sustainable agriculture doesn’t, I think, have to look one specific way,” Holcomb said. “As more and more people live in cities, as the population continues to grow, there have to be ways for people to grow food in a sustainable manner where the people are. People love local produce, and Maine has an incredible sustainable agriculture scene, but we have a long dark winter.”

The Brunswick project will fight the cold with strategies such as solar panels, radiant heat flooring and an “energy curtain” that can be used as a shade in summer or an energy-efficient curtain in winter. The biggest weapon, if they can raise enough money for it through an upcoming $25,000 Kickstarter campaign, may be the plan to recapture the heat from the commercial kitchen and café and use it to heat the greenhouse.

Stadler says the kitchen at Tao Yuan often gets so hot, the staff props open the outside door even in the middle of winter. Why waste all that energy? It’s like tossing money into the snow.

The entire building, Stadler says, is built to be “smart” about the way it uses energy. If it works, the payoffs will be big.

“Your food costs go down, and you’re getting a product that will last you twice as long because it’s picked and in your fridge,” Stadler said. “There’s no transportation. There’s no sitting in a farmers market stand for three hours before you pick it up. There’s no driving it down for two hours just to get it to the farmers market.”

Stadler and Holcomb hope to hire student interns to help run the place. They’re working on an arrangement with Harpswell Coastal Academy, and may also invite students involved with aquaponics at the University of Southern Maine in Gorham.

“Once you get (the system) cycling, then the idea is that it is an ecosystem,” said Holcomb, who also works as a server at Tao Yuan, and is getting a master’s in business administration from the University of Southern Maine. “It needs to be maintained, and it needs to be closely watched, because if something goes wrong, it can go wrong quickly and on a really big scale. If something is off, you could kill all your fish in a day.”

From the outside, the greenhouse – the structure, along with the energy curtain and grow lights, came from a Portland company called ArchSolar – looks almost complete. But the inside is still pretty much a shell, awaiting the arrival of the solar panels and greenhouse glass from China, while the scream of buzz saws and other equipment from construction workers on the job dampens the noise of traffic streaming by.

The next big steps will be making the fish tanks water-tight, building the grow beds, and adding plumbing, Holcomb said. The greenhouse is expected to cost about $200,000, and the café and commercial kitchen about $1 million, according to Stadler. April Robinson, the pastry chef at Tao Yuan, will own and operate the café, which will serve breakfast and lunch, a menu of pastries and modern American food.

The greenhouse will house two 4-foot-deep fish tanks, each 5-by-15 feet, plus a dozen or more 4-by-16-foot grow beds of different types. The system will use 5,000 gallons of water.

As for the fish, the plan is to use rainbow trout from a private fish hatchery. Tilapia works better, Stadler says, “but no one wants to eat tilapia. It makes me sad, but it’s a reality of our society that everyone associates tilapia with childhood fish sticks.”

“The fish is really a secondary,” she continued. “It’s a byproduct of the system. It will be a rare moment when you see trout on the menu, but you’ll see produce all the time.”

The plan is to start with plants that grow easily in an aquaponic greenhouse, and are in high demand at her restaurants – leafy greens, pea shoots and microgreens. Next, they’ll experiment with Asian herbs and vegetables. Stadler and Holcomb call this “the fun stuff.”

“I really want to try growing rice paddy herb because it grows in rice paddies, and being an aquaponic system it makes sense that that would thrive in the water,” Stadler said. “And I love rice paddy herb.”

The chef is excited to try growing wasabi, and would love to have a reliable source of winged beans. “We’ve ordered them, but half of them are moldy before we even get to touch them,” she said.

Then there’s celtuce, which has a thick, asparagus-like stem topped with light green leaves.

“It’s very edible, but the outside is super, super bitter, so you need to peel off the exterior,” Stadler said. “If you don’t peel it, if you leave any of the skin on it, it will blow your palate with bitterness.”

Peel it down to the core, though, and “it’s sweet and delicious.”

ONE OF JUST A FEW

Stadler and her mother, Cecile, who is also her business partner, started talking about having their own farm to supply their restaurants years ago. It’s a model used by several other restaurants in Maine, including Miyake and Vignola Cinque Terre in Portland and Primo in Rockland. They wondered what they could do that would also be “helpful for Maine.”

Stadler mentioned the idea to Holcomb, who is her oldest friend; they went to preschool together. Holcomb had gone into agriculture and was bouncing around from farm to farm on the East Coast when Stadler was opening Tao Yuan and Bao Bao.

When the Stadlers began to focus on aquaponics, Holcomb recalled, “Cara called me and said ‘Hey, do you want to move to Maine and help me make this happen?’ ”

It was 2013, and Holcomb was working in New York. She quickly packed up her things and moved to Maine.

“I had been organic farming in soil on a traditional farm, so for me aquaponics was a totally new way of growing things,” Holcomb said. To get herself up to speed, Holcomb visited the University of Maine’s Center for Cooperative Aquaculture Research in Franklin, which had an aquaponics demonstration project (it closed in 2015, unable to keep a greenhouse warm enough for winter production, according to its website), and she attended a workshop at the University of New England, where another aquaponics project is about to expand, according to Jeri Fox, an associate professor of aquaculture. Holcomb also reached out to Carey Phillips, a Bowdoin College emeritus professor of biology with an aquaponics project in South Carolina. Holcomb and Phillips collaborated on the Canopy Farms system, “but it’s much more his design,” she said.

Around the country, a few other restaurateurs have embraced the idea and are tailoring their systems to their own restaurants. In Minneapolis, Gandhi Mahal has a system that produces, according to the restaurant’s website, Malabar spinach, cilantro, hot peppers, salad greens, ginger, turmeric and curry leaf. Minneapolis winters are as tough as Maine’s, but the restaurant got around that by putting its aquaponics system in its basement. They call their cuisine “basement to table.” Page Restaurant in Sag Harbor, New York, grows produce in four aquaponic systems, including in the basement and on the walls.

BAO BAO, BUGS AND BUZZ

Stadler has always been the ambitious sort, according to her mother, the kind of person who had a 10-year plan by the time she was 16. She’s also an experimenter, most recently hosting a pop-up edible insect dinner at Bao Bao Dumpling House. Stadler said she wanted to do it because “Bugs are the future, and very much our past and present, depending on the culture.”

Food & Wine magazine named Stadler one of the country’s 10 Best New Chefs in 2015, an honor that goes to chefs age 30 or younger who are “likely to make a significant impact on the industry for years to come.” In 2016, Condé Nast Traveler listed Stadler as one of its 10 Young Chefs to Watch, a group of chefs age 30 and under who are “making outsized impressions around the world.” She’s been a semifinalist for the James Beard Rising Star Chef of the Year award four times, and a finalist once.

Stadler says she and her mother “did really well” in the first few years of Tao Yuan, and they could have just sat back and enjoyed the ride. But they wanted to find ways to build the company, provide good jobs for employees who want to grow with the company, and give something back to the community that contributed to their success. The aquaponic greenhouse is part of that plan.

Meredith Goad can be contacted at 791-6332 or at:

mgoad@pressherald.com

Twitter: MeredithGoad