Yet a growing part of the company’s business is being devoted to something decidedly unindustrial: edible walls — metal panels filled with soil and seeds and hung vertically.

They may sound like a piece of Willie Wonka’s chocolate factory. In fact, they are the latest development in green roof technology. Like green roofs, edible walls include a thick layer of vegetation on the outside of buildings to provide insulation and reduce heating and electricity costs.

But unlike green roofs — and their vertical cousins, green walls — edible walls also produce fruit, vegetables and herbs in far less space than typical gardens. That’s why advocates of urban farming have embraced them as a way to lower food costs, increase nutritional quality and cut fuel consumption and carbon emissions by using fewer delivery trucks.