Chickpeas have become the first crop to be grown and harvested in simulated lunar soil, according to a new study. 

With Nasa aiming to have humans living and working on the Moon in the next 10 years through its Artemis programme, many are wondering what these astronauts will eat. In a study led by the University of Texas at Austin, researchers have been looking into what it will take to grow crops on the lunar surface. 

Lunar regolith, commonly known as moon dirt, lacks the microorganisms and organic material required for plants to grow. While it contains some essential nutrients and minerals, it also contains heavy metals that could be toxic to plants.

Sara Santos, the principal investigator of the project at the University of Texas Institute for Geophysics, asked: “How do we transform this regolith into soil? What kinds of natural mechanisms can cause this conversion?” 

For their study, the researchers used simulated mineral-based regolith from Exolith Lab. Based at the the University of Central Florida, this lab provides realistic, scientifically accurate simulated soils from the Moon, Mars and asteroids for use in space missions. 

To this regolith the team added vermicompost, a by-product of red wiggler earthworms rich in essential plant nutrients and minerals and has a diverse microbiome. These earthworms are taken on space missions and produce this compost by consuming food scraps and other organic materials that would otherwise be thrown away, such as cotton-based clothes and hygiene products. 

The team chose the compact and resilient ‘Myles’ variety of chickpea for their study. Before planting it in the regolith and vermicompost mix, they coated it with the fungi arbuscular mycorrhizae, which helps aid growth by reducing the uptake of heavy metals. 

They found that mixtures of up to 75% regolith successfully produced harvestable chickpeas. However, any more regolith than this and the plants showed signs of stress and early death. However, the stressed plants were still found to survive longer than chickpeas that weren’t inoculated with fungi, showing their importance to plant health. 

The researchers also found that the fungi were able to colonise and survive in the simulant, suggesting they would only need to be introduced once in a real-world growing setting.  

Although harvesting the chickpeas is a big milestone, how the legumes taste and their safety is still an open question. The researchers are now looking to determine the nutritional content of the chickpea and ensure toxic metals were not absorbed during the growing process. 

Jessica Atkin at Texas A&M University, first author on the paper, said: “We want to understand their feasibility as a food source. How healthy are they? Do they have the nutrients astronauts need? If they aren’t safe to eat, how many generations until they are?”  

Their study – ‘Bioremediation of lunar regolith simulant through mycorrhizal fungi and plant symbioses enables chickpea to see’ – has been published in the journal Scientific Reports.