Astronauts might be able to use asteroid soil to grow crops

Astronauts might one day dine on salad grown in asteroid soil.

Romaine lettuce, chili pepper and pink radish plants all grew in mixtures of peat moss and faux asteroid soil, researchers report in the July Planetary Science Journal.  

Scientists have previously grown crops in lunar dirt (SN: 5/23/22). But the new study focuses on “carbonaceous chondrite meteorites, known to be rich in volatile sources — water especially,” says astroecologist Sherry Fieber-Beyer of the University of North Dakota in Grand Forks. These meteorites, and their parent asteroids, are also rich in nitrogen, potassium and phosphorus — key agricultural nutrients. Pulverizing these types of asteroids, perhaps as part of space mining efforts, could potentially provide a ready supply of farming material in space.

Fieber-Beyer purchased a material that mimics the space rocks’ composition and gave it to her graduate student Steven Russell. “I said, ‘All right, grow me some plants.’”

Russell, now an astrobiologist at the University of Wisconsin–Madison, chose a type of radish, lettuce and chili pepper — all of which have grown aboard the International Space Station. He, Fieber-Beyer and their colleague Kathryn Yurkonis, also of the University of North Dakota, compared how the plants grew in only faux asteroid soil, only peat moss and various mixes of the two.

Peat moss keeps soil loose and improves water retention. In all mixtures with peat moss, the plants grew. Faux asteroid soil on its own, however, compacted and couldn’t retain water, and so plants couldn’t grow.

Next, Fieber-Beyer will try growing hairy vetch seeds in that faux asteroid dirt, let the plants decay and then mix the dead plant matter throughout the soil. That, she says, could ensure that the soil doesn’t compact. Plus, seeds weigh a lot less than peat moss, making them easier to carry to space to help with any future farming attempts.