It’s all very well trying to eat local in a place like Rome or San Francisco, where the climate is relatively benign all year round and you can grow a great deal of produce without too much difficulty. But what do you do when you are at an altitude of more than 2000 metres with a growing season that is usually less than three months long? You do what you can, which in the case of Elkstone Farm, near Steamboat Springs in Colorado, means building four greenhouses, one of which is capable of ripening figs, citrus and even, occasionally, bananas. But it isn’t all greenhouses. Outdoors there’s a tangle of many different kinds of annual and perennial crops, which during the short growing season provide an abundance of fruits and vegetables.