Farmers are making inroads supplying local food to hungry city foodies, but many producers are trying to grow more food in urban centers. City real estate is at a premium, so some producers are finding more space by using what’s called “vertical farming,” and going up rather than spreading out. Growers across the country are heading indoors, using greenhouses and hydroponics – growing plants in a water and nutrient solution instead of soil and using lamps to replace sunlight. Vertical farming