In The Martian, fictional astronaut Mark Watney survives the wasteland of Mars by growing potatoes in lunar soil—with a bit of help from human poop. The idea may not be so far-fetched. In a preprint posted this month on bioRxiv, researchers show potatoes can indeed grow in the equivalent of Moon dust, though they need a lot of help from compost found on Earth.
As NASA researchers plot out sustained Moon bases, they are considering crops such as the potato, which is nutrient- and calorie-dense and adaptable to different environments. The work provides “in-depth analysis to start to answer the questions that need to be answered” to ensure the success of these long-term missions, says Jared Long-Fox, a lunar scientist at the University of Central Florida who was not involved with the work.
To make the discovery, scientists first had to re-create lunar regolith—the loose, powdery layer that blankets the Moon’s surface. To replicate that in the lab, David Handy, a space biologist at Oregon State University (OSU), and his colleagues used a mix of crushed minerals and volcanic ash that matched the chemistry of the Moon.
But lunar regolith is entirely devoid of the organic matter that plants need to grow. “Turning an inorganic, inhospitable bucket of glorified sand into something that can support plant growth is complex,” says Anna-Lisa Paul, a plant molecular biologist at the University of Florida not involved with the work. So Handy and his colleagues added vermicompost—organic waste from worms—into the regolith. They found that a mix with 5% compost allowed the potatoes to grow while still emulating the stressful conditions of the lunar environment. After almost 2 months of growth, the team harvested the tubers, freeze-dried them, and ground them up for further testing.
Analysis of the potatoes’ DNA showed stress-related genes had been activated. The potatoes also had higher concentrations of copper and zinc than Earth-grown ones, which may make them dangerous for human consumption. The plants’ nutritional value, though, was similar to traditional potatoes—a surprise to the scientists, who expected lower levels of nutrition “because the plants might have been working overtime to overcome certain stressors,” Handy says.
Still, Long-Fox notes that the study didn’t replicate other hazards of the Moon, such as constant radiation and the vacuum of space. He also would like to see the experiment repeated in actual lunar soil, not just simulants, and thinks NASA’s current lunar plans could help. “As we move forward with the Artemis program, getting bigger and more diverse lunar samples available is going to be really important,” he says.
In the meantime, Handy’s team is already onto its next experiment. By testing different varieties of potatoes grown in the regolith, the scientists are hoping to discover which ones fare best, says co-author Aymeric Goyer, a plant biochemist at OSU. “Eventually, maybe geneticists can select and breed for potatoes that are better adapted to the Moon.”
Correction, 18 March, 10:40 a.m.: This story has been corrected to clarify Jared Long-Fox’s current affiliation.