The three Georgetown grads behind Sweetgreen — the fast-casual restaurant now with 10-plus locations across the U.S. — are much more than salad slingers. The savvy foodtrepreneurs host their third, sold-out Sweetlife festival ( tomorrow at Merriweather Post Pavillion with Avicii, Kid Cudi and the Shins headlining. Like their restaurants, the bash marries local eats with eco-practices. But as Nathaniel Ru, Nicolas Jammet and Jonathan Neman (left to right) prove, making healthy decisions doesn’t mean sacrificing fun.

Have the three of you always had an interest in music?
Neman: Music has always been a big part of our lives. When we opened the original Sweetgreen, there was a huge debate over what song we’d play first. We went with Robot Rock by Daft Punk.

Where did you get the idea for the Sweetlife festival?
Neman: When we opened our second store, it wasn’t doing very well. So we went to the Guitar Center and bought a big speaker and started DJing outside every weekend. It became more than just food: People got to know us and heard music they loved or had never heard before but liked. After a few block parties, we decided to throw a festival in our parking lot.

How will this year’s festival be different from last year’s?
Ru: We’re placing a greater emphasis on food. We’ve brought together our favorite chefs from the East Coast; people who love our mission. The “Food Forest” will give people the opportunity to eat local ingredients. And there will be hamburgers and hot dogs, but they’re organic and from sources we trust.
Neman: Last year there was one stage, and this year there’s two with more than 20 bands.
Jammet: And this year there will be shuttles all over the city that will make getting to Merriweather Post Pavilion seamless.

Who would be your dream act?
Jammet: LCD Soundsystem.
Neman: White Stripes.
Ru: Daft Punk.

What measures are you taking to make the festival green?
Jammet: There are solar panels on top of the stage. Everything will be compostable. You’ll see “energy zones,” like a huge seesaw that you can get on and charge your phone with the energy generated. And concertgoers can redeem trash they’ve collected for prizes like bottles of Honest Tea or a recycled wallet.

How did you manage to make collecting trash cool?
Jammet: We try not to be preachy about our message of living the sweet life. It means making healthy decisions and having fun at the same time. We’re trying to show people they can drink organic beer, eat a sustainable meal and still have a really good time at a rock concert.