Sadly, if Mark Watney really had to try and survive by growing potatoes in his own shit, he would still be on Mars – and very dead.

What Andy Weir didn’t know when writing “The Martian” was that the soil there contains chemicals such as perchlorates and other nasties that mean simply trying to farm the soil likely wouldn’t work.

While it would probably be theoretically possible to recondition areas of land over time – a more likely solution for any future Martian colony would be hydroponic farming: Growing food without soil using re-claimed water and balanced nutrients to create a “closed loop”, self-sustaining system.

NASA has been investigating this approach for years – and even has a dedicated facilitiy on the ISS to conduct food research.

Another way in which “The Martian” differs from the likely reality is that any farms on Mars – as well as the colonies themselves – would probably have to be underground to protect the crops – and crews – from radiation. Another reason why hydroponics would be the answer…