We would need to devise ways of producing food where none exists, because depending on supplies from Earth would neither be sustainable or practical.

In the 2015 blockbuster movie "The Martian," Mark Watney (Matt Damon) is famously depicted planting potatoes in a makeshift greenhouse after getting stranded on Mars during an epic storm that forced the rest of his crew to abandon their mission. Using vacuum-packed potatoes from the mission's base, Watney planted them using the planet's "soil," produced water from chemical reactions and fertilized his burgeoning potato crop with the crew's freeze-dried poop.

It seems like a pretty straightforward method of cultivating plants on Mars — but deceptively so.