Berlin Supermarket Grows Lettuce on Its Own Rooftop

The freshest lettuce at REWE's Lankwitz store in Berlin doesn't arrive by truck. It comes down the stairs.

The grocery store built a working farm on its own roof. Lettuce grows in a greenhouse directly above the shopping floor, gets harvested in the morning, and lands on shelves within hours.

The setup turns the entire building into a closed loop system. Waste heat from the store's refrigerators rises to warm the greenhouse. Rainwater collected from the roof waters the plants. Solar panels provide some of the power.

The farm uses hydroponic technology, which means almost no soil and a harvest cycle of just over three weeks. Skylights throughout the store let shoppers look up and see what's growing above them.

"We don't even have an extra truck on the road that usually is necessary to transport the goods from the producer to the central distribution," said Leschke, the REWE project lead. The supply chain is literally a staircase.

The greens don't just stay in this one store. They also go to other REWE locations across Berlin, spreading the benefits beyond the neighborhood.

The Ripple Effect

Prajal Pradhan, an associate professor at the University of Groningen, studies urban agriculture across Europe. His research found that rooftop and ground-based urban farms could supply up to 28 percent of Europe's total vegetable needs.

That's around 20 million metric tons of vegetables per year grown in cities. Berlin alone could grow a significant share of its own vegetable needs within city limits.

But Pradhan emphasizes one important point: supermarket rooftop farms shouldn't replace community gardens. "Getting people together from a dense city and sharing agricultural knowledge among them helps bring the community together," said his co-author Stepan Svintsov.

REWE plans to build at least 20 more rooftop farms over the next decade, with at least one in every region within five years. The goal is reducing dependence on supply chains that stretch across continents.

For now, customers at Lankwitz can take tours of the facility and watch their food grow just one floor up. One shopper planning a caprese salad specifically chose the greenhouse greens because, as she put it, the roof is right there.