Business Green: For years the concept of vertical farms has been consigned to the pages of architect’s notebooks, but now a British-Canadian firm is poised to turn vertical farming into a reality — albeit on a smaller scale than the farm skyscrapers you find in science fiction novels. Cornwall-based Valcent Products has developed a vertical horticultural system that promises to slash the amount of land, water and energy used to produce crops typically grown in greenhouse conditions. “The idea …