Grow your own Martian salad

If recent news has made you want to leave the planet, then you’re not alone. There is research on creating offworld colonies in the solar system, with a focus on the Moon and Mars. Elon Musk is said to be planning a colony on Mars, sending the first colonists into space, assuming his Starlink satellite network doesn’t send someone to the heavens sooner. Getting people to Mars is relatively easy compared to keeping them alive once they’re there. For example, how will you grow food?

Where can you get a plot of Martian land to grow food?

In order to grow a Martian salad as authentically as possible, you’ll need some Martian soil. You can’t get real Martian soil. No Martian soil has been brought back to Earth and Mars doesn’t actually have soil, it has regolith. Regolith is ground rock, there’s no organic component that turns the rock into soil. However in a recent video on Tom Scott’s YouTube channel, Tom Carroll (of Aspect Science) experiments with a pretty good simulation of Martian regolith. So you can copy him and run your own experiments.

Given the effort and enthusiasm, I feel a bit of a curmudgeon pointing out one of the problems with the video. Mars has no magnetosphere. The Earth does, and it protects inhabitants from a lot of cosmic nastiness. It might well be the case that settlement would be best underground with plenty of soil to shield colonists from cosmic radiation. If that’s the case, would greens be something grown hydroponically? This would eliminate the need to process the regolith to remove perchlorates. However, if you want to re-enact the potato scene from The Martian, then regolith would be useful.

So while I’m not convinced this is how Martian salad will grow, as an experiment for home, “grow your own food in Martian soil” is deeply cool.

Does a Martian diet have to be vegetarian?

It would appear that plants will be a major element of any future space colony, simply for energetic reasons. If you eat animals, they will need to eat plants, and this increases the energy you need dramatically, to create the same calorific content. So how would a Martian diet differ?

Cannon and Britt have published an article in New Space on how you could feed one million people on Mars. Plants will play a large part in the Martian diet, if they’re correct. They propose that plants will be grown underground either with hydroponics or treated Martian regolith. They do see a role for meat, if you think of insects as meat. They also suggest that cultured meat-like products will be on the menu.

As we don’t have much of the fundamental questions of how we will put people on Mars answered, researching how to feed people once they’re there might seem a bit of an indulgence. Why not fix Earth first? Like a lot of space research, working on Martian agriculture strips out quite a few confusing variables and frames questions in new ways that can then have applications on Earth. In fact, Cannon and Britt have a website that allows you to try eating like a Martian right now.

One of the features of the Martian diet is that it’s not simply ‘plants’. Plants have different demands and, on a barren planet, moving to a diet that uses plants that are relatively frugal with water is a much better idea than growing indiscriminately. If you’re living on a planet where climate change is putting pressure on water supplies, this could be useful information to have.

A Martian diet might also help mental health – if prepared correctly

A major factor in planning to operate a garden in space is the actual time used for the activity of gardening. This might seem like time that could be spent doing SCIENCE. Yet it might actually help a crew concentrate on their other work. Research is showing that, like on Earth, gardening is an emotional boost, but could also have further mental benefits.

The February 2020 issue of Life Sciences in Space Research has an article by Zhang and colleagues, Synergistic effects of edible plants with light environment on the emotion and sleep of humans in long-duration isolated environment. This records some of the experiments in the Lunar Palace 365 project. This put four students into an isolated environment where they grew much of their own food and dealt with problems set by experimenters.

For one of the experiments, the team compared the effects of growing Strawberry, Purple Rape and Coriander on the crew. The authors report: “Strawberry had a better effect than purple rape and coriander on improving positive emotion.” Given coriander is delicious and strawberries are a pain, this might not be a replicable result. 

Another intriguing finding was how plants affected sleep quality. The plants could aid the crew in falling asleep. “The results of this study indicated that coriander could reduce sleep latency obviously than purple rape and strawberry. We suspected that the volatile compounds of coriander play a main role in reducing anxiety and promoting sleep,” Zhang and colleagues write. “However, the regulation mechanism of human sleep by coriander plants in an isolated environment remains unclear, and further research is needed.”

As a home experiments go, locking people away for a year or more has its problems. In contrast, growing a Martian salad looks like a fun project for a few weeks. If you have just a few minutes, rather than weeks, Aspect Science also looks like it has some other videos of botanical interest.