On a former steel mill site on Chicago's South Side, a 12-story building filled with lettuce, herbs, and microgreens is now the largest vertical farm in North America. GreenStack, the startup behind the facility, began its first commercial harvest this week, shipping produce to over 200 grocery stores across Illinois, Indiana, and Wisconsin.
The numbers are staggering: 180,000 square feet of growing space stacked vertically, producing an estimated 2.1 million pounds of leafy greens per year. The facility uses 95% less water than field agriculture through a closed-loop hydroponic system, and generates zero agricultural runoff.
Lettuce growing under tuned-spectrum LED arrays at GreenStack."We're proving that industrial-scale vertical farming isn't just viable — it's inevitable," said GreenStack CEO Michael Torres. "Our cost per head of lettuce is now competitive with California field-grown, and we're located 20 minutes from our customers instead of 2,000 miles."