From the outside, indoor vertical farms are unimpressive - just huge, non-descript warehouses. Step inside and immediately the air changes, it's moist, sometimes sweet, always verdant. It wafts amongst soft, coloured lighting; a strange futuristic Eden of sprouting greenery cascading from the heavens, nursed, monitored and tracked by all manner of analysts and machines. Welcome to the world of indoor Vertical Farming. It's not just the environment that sucks you in - the people too.