Although Mars may once have been warm and wet, the Red Planet today is a frozen wasteland. Most scientists agree, it’s highly unlikely that any living creature –even a microbe– could survive for long on the surface of Mars. When the first humans travel there to explore the Red Planet up close, they will have to grow their food in airtight, heated greenhouses. The Martian atmosphere is far too cold and dry for edible plants to grow in the open air. But if humans ever hope to establish long-term colonies on their planetary neighbor, they will no doubt want to find a way to farm outdoors. Imre Friedmann has an idea of how they might take the first step.