Thomas Schneider, the founder and executive director of Rooftop Roots, in one of his gardens. (Keith Lane/for The Washington Post)

People always ask Peaches for her peppers.

Wanda “Peaches” Dickerson, 58, makes relish from peppers grown in the garden atop her apartment complex in Alexandria, Va., relying on an old family recipe but adding a “secret” twist. Neighbors waylay her everywhere — in hallways, in the elevator, as she’s leaving to go grocery shopping — to ask for a bottle.

Someday, she wants to turn her relish into a small business. “This is a dream for me,” Dickerson said.

The community plot where she picks her peppers was built by Rooftop Roots, a nonprofit group with a mission of installing gardens on rooftops of affordable housing across the D.C. area. It was founded in 2011 by Thomas Schneider, a consultant for the Environmental Protection Agency until he quit six months ago to focus on his start-up.

Schneider, 35, established the nonprofit with three goals: to promote social, environmental and economic justice by building gardens in low-income neighborhoods.

He says the gardens are social because they offer people a green space to relax in; environmental because they yield free produce without the carbon footprint of shipping; and economic because Schneider hopes to eventually pay some of the area’s poorest residents to tend the gardens.

“We want to basically scale this to a point where we’re able to provide full-time jobs — to use the nonprofit banner to generate revenue and pay people $40,000 or $50,000, provide health care, financial literacy,” Schneider said. “I think that’s when we’re getting close to success.”

Rooftop Roots has installed about 60 residential, commercial and community gardens around the region since it launched.

Seven are community gardens atop affordable housing com­plexes or in public parks near low-income neighborhoods. The organization uses the money it makes from the residential and commercial gardens — which it charges for — to fund the community ones — which have no cost for their users. The gardens cost between $5,000 and $10,000 to build and maintain.

So far, Dickerson is the only affordable housing resident Schneider can afford to pay to maintain one of his gardens. Dickerson works in the garden at the Station at Potomac Yard Apartments for several hours a week in exchange for a monthly stipend of $300. Schneider runs the organization with his wife, Joni Miller, and four part-time workers who help with the heavy lifting during garden installations.

Wanda “Peaches” Dickerson, a resident of the Station at Potomac Yard Apartments, looks over her rooftop garden. (Keith Lane/For The Washington Post)

Canned vegetables from Wanda “Peaches” Dickerson sit ready to be shared. (Keith Lane/For The Washington Post)

“It’s the space that we need to grow out the most, admittedly,” he said in an interview at the Potomac Yard garden, bending over a tomato plant to train it with twine.

Elmer Brown, an 88-year-old retired maintenance worker who lives in federally subsidized housing in Northeast Washington, has been planting vegetables in a Rooftop Roots garden near his home for about three years. Brown has come to love the “glorious” taste of homegrown eggplants, strawberries and kale.

What he loves more is how it has allowed him to get to know his neighbors. People who had lived near one another for years without exchanging a word began meeting, chatting and befriending one another as they tended adjacent plots of dirt, Brown said.

“The basic thing is the camaraderie [with] other neighbors, people of all ethnicities,” Brown said. “It’s a community effort, so well-conceived. I love it.”

Brown said the neighborhood recently planned to hold a potluck. The only rule: Every attendee had to cook and bring something they grew in the garden.

Rooftop Roots combines Schneider’s two passions: the environment and food. He earned a degree in wildlife biology at Virginia Tech and went to work for the EPA’s emergency management office after college, where he helped the agency prepare for and respond to oil spills.

He has also always loved cooking and, more recently, growing his own food. While working for the EPA and living in a rental house with a childhood best friend, he began planting vegetables in his backyard.

A variety of vegetables are grown on the rooftop of the Station at Potomac Yard Apartments. (Keith Lane/for The Washington Post)

Schneider remembers the day his hobby became something more. He was sitting on the balcony of a friend’s Navy Yard apartment after a Nationals game, looking out at the roof of a large office building, when he had an idea.

“It was probably like 10,000 feet of just blank space, and I was like, ‘Well, that would be cool if we could do something with that roof, grow vegetables or something,’ ” Schneider said.

So Rooftop Roots was born.

Initially, the plan was to grow vegetables and give them to food banks. Over time, though, Schneider’s vision shifted. He also learned, through trial and error, what to do — and what not to do — when setting up a rooftop garden.

Walking around the roof at Potomac Yard, one of the first community gardens he built, Schneider rattled off an inventory of past mistakes. Always make sure the roof is easily accessible on foot. Never build in a spot that doesn’t have water access.

He said he has learned which plants do well on rooftops and which don’t. Rooftop Roots ­focuses on vegetables that grow to smaller sizes, meaning they need less soil depth, and permit multiple harvests. That list includes tomatoes, lettuce, herbs, peppers, okra, cucumbers, squash, green beans, beets, collards — and, this fall, it will expand to “kalettes,” a hybrid plant bred from kale and Brussels sprouts.

His wife, who works at local farmers markets, discovered the crossover veggies at work and mentioned them to her husband. This is how it often goes, both say: Miller figures out what people are buying and tells Schneider, who grows it in his community gardens. The couple joke that they have a symbiotic relationship. In many ways, they are in sync: Both are drawn to brown earth and leafy green vegetables. Both want to spend their lives around vegetables. Both want more people to grow their own food.

“We’re educating people that not everything comes from the grocery store and looks amazingly beautiful and is picture-perfect, but look, homegrown food — even if it sometimes has a few blemishes — tastes a million times better and is certainly better for the environment,” Schneider said.

Dickerson put it another way.

“Dirt is good for you,” she said.