Lines began forming outside of Homegrown’s door as soon as the new sustainable sandwich shop opened in Fremont.

During its first two weeks of business, Homegrown closed early every day after selling out of food, said cofounder Ben Friedman, a self-titled “sandwich environmentalist” and Mercer Island High School graduate.

“Being on the cutting edge of the restaurant scene and food scene is fun,” said Friedman. “We’re trying to do something that few people have succeeded at — an organic quick service concept. It’s something there’s a need for. I think that a lot of people eat organic and local food at home, and when they go out to eat, they don’t want to sacrifice that.”

Friedman and business partner Brad Gillis, friends since before kindergarten, opened Homegrown in March after more than a year of planning and research. Their vision was an environmentally friendly business with a sustainable menu.

“The passion for the environment has always been there, from when we were very young, and the sandwiches came as a self-fulfilling prophecy,” said Friedman, who said that he and Gillis began making sandwiches years ago for friends and family. Gillis credited much of their current success to their families and mothers, who Friedman described as good cooks.

Gillis and Friedman, both 23, attended West Mercer Elementary together and graduated from Mercer Island High School in 2004. Friedman went on to Boston University, where he earned a degree in advertising and sociology, and Gillis graduated in environmental studies and geology from Bowdoin College, Maine.

“I knew that I wanted to do something with the environment or working in a business that had some part in bettering the environment, so it’s been a real treat to do that while making food,” said Gillis, the chief sandwich architect.

A typical day at Homegrown for Friedman and Gillis begins at 7:30 or 8 a.m. and involves preparation for the lunch rush between 12 and 2 p.m.; working the counter; managing staff and spending three to four hours later in the afternoon doing office work.

With a staff of 17, Homegrown churns out its own sauces and condiments for its sandwiches, which include grilled portobello, blackened cod, flank steak and Euki pulled pork, among others — hot and cold.

Mayonnaise, ketchup and most mustards served at Homegrown do not come from a grocery store; they are made in-house. After all, Homegrown’s goal, according to a statement on its Web site, “is not only to create sandwiches out of sustainable ingredients, but also to make sandwich creation sustainable itself.”

“It’s like taking a simple deli sandwich idea and making it as complicated as possible to do,” said Friedman. “It’s really challenging … to make everything from scratch.”

Homegrown uses a mix of organic and local ingredients — cheese from Beecher’s Handmade Cheese in Pike Place Market; bread from Boulangerie Nantaise, an organic French bakery in Seattle, as well as Grand Central Baking Company, and other items from not only local Washington farms, but also Idaho, Oregon and California — the source of year-round avocados and lemons. Vegetables are ordered and delivered daily for freshness.

The menu also features salads, soups and sides.

“We try to take a lot of cues from the fine dining world, with interesting ingredients; and being able to do that all in-house, we’re able to come up with a better product,” said Gillis.

Homegrown is located at 3416 Fremont Ave. N., Seattle, 98103. Business hours are 11 a.m.-9 p.m., Monday through Saturday, and 11 a.m.-4 p.m., Sunday. At the end of the summer, Homegrown will offer a box lunch service and delivery for Seattle businesses.

For more information, call (206) 453-5232 or go to www.eathomegrown.com.