kkleiner writes: "Short on arable land? One solution would be to plan up. Singapore, a small country that imports most of its food, has now begun selling vegetables from its first vertical farm. And even while they’re more expensive the vegetables are already selling faster than they can be grown. If the farms prove sustainable – both technologically and economically – they could provide a much desired supplement to Singapore’s locally grown food and serve as a model for farming in other land-challenged areas."