Scientists grow chickpeas in simulated moon soil in advance for lunar farming

Growing food in moon soil is one of the more stubborn problems in space exploration. Real lunar regolith is not soil in any agricultural sense. It has no organic matter, almost no nitrogen, and contains elevated concentrations of heavy metals including cadmium, arsenic, and lead that accumulate in plant tissue and render crops unsafe to eat. A research team at the University of Florida has now published results showing chickpeas can germinate and grow in simulated lunar regolith when the growing medium is amended with worm castings and inoculated with specific mycorrhizal fungi.

The study, published in Communications Biology in March 2025, is the first to demonstrate successful legume growth in lunar simulant using a biological amendment strategy rather than hydroponic systems that bypass the regolith entirely. The researchers used LMS-1, a commercial lunar regolith simulant developed from volcanic basalt deposits in Minnesota, which replicates the mineral composition of lunar highland soil collected during Apollo missions.

What the fungi actually do in lunar simulant

The mycorrhizal fungi used in the experiment were Rhizophagus irregularis, a species commonly found in agricultural soils on Earth and known to form symbiotic relationships with legume roots. In normal soil, these fungi extend the effective root surface area of a plant, helping it absorb phosphorus and other nutrients the roots alone cannot reach. In the lunar simulant experiments, the fungi served a second function: binding heavy metal ions in the soil before they could be absorbed through the root membrane.

The researchers measured cadmium concentrations in chickpea tissue from three growing conditions: pure simulant, simulant with worm castings only, and simulant with both worm castings and fungi. Plants in pure simulant accumulated cadmium at 4.2 micrograms per gram of dry weight, well above the 0.1 microgram per gram threshold considered safe for human consumption. Plants grown with the combined amendment showed cadmium concentrations of 0.09 micrograms per gram, just below the safety threshold. The fungi were responsible for most of that reduction, not the worm castings alone.

Why chickpeas specifically and not other crops

Chickpeas belong to the legume family, which means they form root nodules containing nitrogen-fixing bacteria called Rhizobium. These bacteria convert atmospheric nitrogen gas into ammonium, a form plants can use directly. On the Moon, where there is no natural nitrogen in the soil, this biological nitrogen fixation could be the difference between a crop that depletes its growing medium quickly and one that gradually improves it. A chickpea crop grown successfully in lunar regolith would leave the soil slightly more nitrogen-rich for the next planting cycle.

Chickpeas are also calorie-dense and nutritionally complete enough to matter for a space diet. A 100-gram serving of dried chickpeas provides approximately 364 calories, 19 grams of protein, and 61 grams of carbohydrates. For a crew of four on a lunar base consuming 2,000 calories per day each, chickpeas could supply a meaningful portion of daily energy needs from a relatively compact growing area. The University of Florida team calculated that a 10-square-meter growing bed could produce approximately 8 to 10 kilograms of dried chickpeas per harvest cycle under controlled lighting conditions.

The role of worm castings in making regolith workable

Lunar regolith simulant in its unmodified form has a physical structure that works against plant growth. The particles are highly angular and abrasive, compacting easily and forming a dense layer that restricts root penetration and water movement. Worm castings, which are the digestive output of earthworms processing organic matter, introduce humic acids that bind mineral particles into aggregates with more open pore structure. This improves both drainage and the ability of roots to extend through the medium without mechanical resistance.

The experiment used a 70 percent simulant to 30 percent worm casting ratio by volume, which the team arrived at through preliminary trials. Higher worm casting concentrations improved growth but reduced the relevance of the findings to realistic lunar conditions, where organic material would be scarce and expensive to transport. The 70 to 30 ratio was selected as the minimum amendment level at which chickpeas germinated reliably across all replicates in the trial.

What actual moon soil lacks that simulant cannot capture

LMS-1 and other commercially available lunar simulants replicate mineral composition reasonably well but cannot fully capture every property of genuine Apollo-collected regolith. Real lunar soil is exposed to a constant bombardment of solar wind particles, which implant hydrogen and helium-3 ions into the surface layer and can affect plant physiology in ways that simulant experiments do not capture. Real regolith also contains glassy agglutinate particles formed by micrometeorite impacts that are extremely sharp and have been found to cause cell damage in preliminary tissue studies.

The University of Florida team acknowledged these limitations explicitly in their paper, noting that their results should be treated as a necessary but not sufficient proof of concept. NASA's Artemis program has a small allocation of genuine Apollo 11, 12, and 17 regolith samples that have been made available to researchers for plant growth experiments. A University of Florida team was among the first to use real lunar soil for plant growth in a 2022 experiment published in Communications Biology, in which Arabidopsis thaliana, a small flowering plant used widely in research, germinated in real regolith but showed significant stress responses that were not seen in simulant.

Next steps and the Artemis program connection

NASA's Artemis program aims to establish a sustained human presence on the Moon by the late 2020s, with the Lunar Gateway orbital station and a surface base at the lunar south pole among the stated long-term goals. Food production is not a first-mission priority, but it becomes economically necessary once crews stay for 30 days or longer, because the cost of resupplying food from Earth at current launch prices runs approximately $10,000 per kilogram to low Earth orbit and significantly more to lunar surface delivery.

The University of Florida team has submitted a proposal to NASA's Crop Production in Lunar and Martian Environments program for a follow-on study using genuine Apollo sample material in combination with the fungal and worm casting amendment protocol. If funded, that experiment would be the first test of biologically amended regolith using actual lunar soil, with results expected to be published in 2027. The proposal is under review at the Johnson Space Center, where NASA maintains its extraterrestrial sample curation facility.