“This is the new green graffiti!” exclaimed Steve Ritz.

Ritz is a grade-school science teacher from the South Bronx. He made the observation – more so an exclamation – during his TEDxManhattan talk in January.

Ritz was describing his classroom, where fruit and vegetables are, quite literally, climbing the walls.

Ritz is among the early adopters of and advocates for a larger movement and emerging trend in urban agriculture: indoor edible walls, or “food walls” — metal panels fitted with soil. According to Ritz, his sixth-grade class grew enough produce on food walls in their classroom to feed 450 people.

The walls, while innovative on their face, are part of a larger narrative around food deserts, regions in the United States – a country known for its supposed bounty – where residents have limited-to-no access to fresh produce. The issue has attracted the attention of celebrities and politicians alike, and has been taken on by a wide range of activists – from Ritz and his sixth-grade classroom to actor Wendell Pierce, best known for his role on the HBO drama “The Wire.” Pierce is opening grocery stores in food deserts. Then, of course, there is First Lady Michelle Obama who is leading efforts aimed at eliminating American food deserts. On Wednesday, the First Lady announced the winners of the Let’s Move! Comunities on the Move video challenge — a program designed to promote wellness and reverse the trend of childhood obesity.

While the correlation between food deserts and obesity was recently challenged in a paper by economist Rolan Sturm at the RAND Corporation, there has been an impetus to find innovative and space-saving ways to grow real food locally particularly in cities, where the best, if not only, local source of food is the corner store selling canned goods and candy.

In response to this need, the urban agriculture movement has promoted many ways of farming the city: from hydroponic (or soilless), concrete greenhouses to green roofs – or rooftop gardens.

But food walls offer solutions to many of the challenges intrinsic to food deserts, from enabling the growth of produce in a city while overcoming urban space limitations to bringing the farm and city one step closer. Despite their simplicity and ability to bring fresh produce straight to places most in need, there’s a reason edible walls have been slow to gain popularity: they simply can’t grow all the produce we need – for example, they are unsuitable for growing rice or corn.

Even though their reach is still limited, the emergence of edible walls is part of something bigger: the start of a shift in agriculture toward city-friendly, space-saving vertical farming.

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