Photo courtesy of Sweetgreen

Swing by the Sweetgreen outpost in Manhattan's trendy neighborhood Nolita any week day around lunchtime, and you’ll find the expected crowd queuing up for custom-mixed salads and grain bowls: a smattering of models, musicians and creative class professionals tapping out emails on their phones. Often, the line stretches all the way out the door. Sweetgreen founders Jonathan Neman, Nicolas Jammet and Nathaniel Ru have made a stunning success of their eight-year-old restaurant chain for riding the wave of organic produce and handpicking locations in neighborhoods like this one, places populated by a health-savvy folk receptive to Sweetgreen’s proffer of farm-to-table fast food. At the Sweetgreen headquarters in Washington D.C., they refer to such folk as “The Sweetgreen Tribe.”

There are only so many people in that tribe, though. Enough to have supported the expansion of Sweetgreen from its first store in D.C., which the founders opened the summer after graduating from Georgetown, to the 40 outlets that will be up and running by the end of this year. (The plan for 2016, according to Neman, is to open at least 20 more.) But if Sweetgreen is going to change the way the food industry operates, which is the aim-for-the-stars goal, that “Sweetgreen Tribe” is going to have to grow. A lot. The company eschews traditional marketing; instead, the founders have taken a novel tack to build its customer base. Their modus operandi, in a nutshell? Get ‘em while they’re young.

On a recent morning up in Harlem, a class of fourth-graders watches, transfixed, as a Sweetgreen staffer explains the concept, “Eat the Rainbow.” Red fruits, she tells them, are rich in antioxidants. Orange vegetables contain alpha and beta-carotene, which help produce vitamin A—essential for good vision and healthy bones, skin and teeth. Yellow produce “bursts with nutrients”: There’s good to be had whether you’re eating lemons or corn. Green, blue, purple—fruit and veggies of every color makes a distinct contribution to health, she explains. “Eat the rainbow” and you’ll grow up fit and strong. The kids nod along.

“Eat the Rainbow” is part of the lesson plan of Sweetgreen in Schools, a four-class curriculum that brings the brand’s healthy living message straight to kids. Launched in D.C. in 2010, the program has expanded alongside Sweetgreen, and thus far has reached more than 5,000 students in low-income areas of the cities where Sweetgreen has stores. And, within the next year alone, Newman predicts Sweetgreen in Schools to double its reach.