Sweetgreen co-founders, from left, Nicolas Jammet, Nathaniel Ru and Jonathan Neman in their company’s D.C. headquarters. (Jeffrey MacMillan)

Investors have tossed a fresh $18.5 million into District-based Sweetgreen to fund an expansion of the salad chain that includes opening its first locations on the West Coast next year, executives announced Wednesday.

The company already has plans to head to Los Angeles, with locations slated to open in West Hollywood and Santa Monica in early 2015. Executives said more California restaurants could be expected, though they declined to say how many.

Sweetgreen has been sprouting restaurants around greater Washington, Philadelphia, New York and Boston since it was founded in 2007. The chain counts 27 locations in all, with two more to open in New York next month.

“This investment is to fuel growth and continue momentum,” co-founder and co-chief executive Nicolas Jammet said. “It is for us to continue to think about how we can elevate the customer experience when it comes to fast food.”

Revolution Growth, a D.C. venture capital fund, led the latest round of investment. Other financial backers include Gary Hirshberg, the founder and chairman of Stonyfield Farm; Scott Belsky, the founder of online portfolio company Behance; and restaurateurs Danny Meyer and Daniel Boulud.

Founded by Georgetown University graduates Jammet, Nathaniel Ru and Jonathan Neman, Sweetgreen applies the fast-casual restaurant model popularized by Chipotle Mexican Grill to leafy greens.

Customers can choose from a menu of house creations, or make their own salad with both garden variety vegetables and more unique options, including roasted curry cauliflower, roasted sweet potatoes and spicy quinoa.

Those customers, which the company refers to as “conscious achievers,” are pegged as educated, culturally curious urbanites who care about fitness and the environment. They’re also willing to pay $10 to $15 per salad.

Sweetgreen’s evolving menu reflects their tastes. The company endeavors to source its vegetables and meat from a stable of local farmers and, as a result, has begun only serving vegetables that are in season.

“We want customers to not just understand, but embrace this idea of eating with the season and where you live in the country,” Jammet said. “For us, that means food is going to taste different in different parts of the country.”

Evan Morgan, an investor at Revolution Growth who sits on Sweetgreen’s board, said he hopes to see the chain add at least another 15 establishments next year. That includes expanding into California and increasing its footprint in existing cities.

But as other fast-growing establishments have learned, perhaps most notably Starbucks, expansion has to be smart if it’s going to stick.

“You want to make sure you nail the real estate, you want to make sure you nail the people, and you want to make sure you nail the operations,” Morgan said.

Revolution Growth first invested in the company last December when the venture fund, which is helmed by former AOL executives Steve Case and Ted Leonsis, funneled $22 million into Sweetgreen’s coffers.

In that time, Revolution has helped Sweetgreen to round out its leadership team with a slate of executives that includes Karen Kelley as president and chief operating officer, and Joel Chrisman as vice president of technology.

“Since we got involved with it a year ago, everything has trended better than our wildest expectations, in terms of the financials of the company ... consumer loyalty and our ability to attract and retain great people to work at the company,” Morgan said.

The latest funding will also allow Sweetgreen to invest in a new online ordering system, part of an effort to cut down on long lines during the lunch hour. The chain already allows customers to pay using a mobile app, and processes 25 percent of transactions that way.

The company also plans to expand its Sweetgreen in Schools program, which brings elementary school students to their nearest salad shop for lessons on nutrition and a taste of Sweetgreen’s menu.

Those curriculum-based programs primarily take place in the District, but executives intend to start them in all of Sweetgreen’s markets next year. “As our company grows our impact also grows,” Jammet said.