Plenty, a startup headquartered in South San Francisco, is building a 100,000-squarefoot vertical farming warehouse (similar to its Bay Area project) near Seattle. The goal: produce 4.5 million pounds of greens annually. Using 20-foot-tall towers, the farm will grow plants, lighted by LED lamps, seeded in a mixture made of recycled plastic bottles (no soil). Water and nutrients are fed in from the top. The company says the method can yield 350 times the produce per acre (without pesticides), and they aim to build these vertical farms outside major cities across the country.