No One Has Tested Fungi on Real Martian Soil
Fungi Won't Grow on Mars — Because Nobody Has Actually Tried
A new review paper calls fungi a promising tool for making Martian soil fit to grow crops. The catch: every experiment it cites used fake soil. The one study that used real lunar material from the Apollo missions produced plants too stressed to be useful.
The paper, published in Frontiers in Astronomy and Space Sciences in April 2026, surveys the literature on using beneficial fungi — species like Trichoderma and arbuscular mycorrhizal fungi (AMF) — to condition lunar and Martian regolith, the loose rock and dust that covers both bodies. The framing is optimistic: fungi can break down stubborn minerals, fix nitrogen, and help plants access nutrients locked in sterile ground. The paper is a synthesis, not a new experiment, and it acknowledges that nobody has ever applied these fungi to actual Martian regolith.
"The literature is dominated by regolith simulants," the authors note — materials engineered to approximate Martian or lunar soil on Earth, not the real thing pulled from another planetary body. Simulants are useful tools. They are not the actual surface of Mars.
The one experiment that came closest used real lunar regolith collected during Apollo missions. Researchers grew Arabidopsis thaliana, a standard model organism in plant biology, directly in the authentic lunar material with nutrient support. The result: plants grew slower and showed a severe stress phenotype, according to the review. The fungi in the current paper were not part of that test. That experiment has not been run.
The iron problem is not hypothetical. Martian regolith contains iron at 12.4 weight percent (w/v%), which is 1,240 times the approximately 0.01 w/v% that most crops can tolerate without stress, the review states. The fungi being studied — Trichoderma, Penicillium, Aspergillus — are not magic. They are organisms with known capabilities and known risks. Trichoderma, Penicillium, and Aspergillus include pathogenic strains alongside beneficial ones, the authors note. Biosafety, strain selection, and performance under Martian radiation exposure remain open knowledge gaps.
Delivery economics are not kind to the in-situ resource utilization (ISRU) scenario — getting nitrogen fertilizers to the International Space Station costs roughly $20,000 per kilogram under NASA commercial pricing, the paper reports. If you are farming Mars, you need to source nitrogen locally or accept that every kilogram you cannot produce on-planet costs roughly as much as a mid-range sedan to import.
There are encouraging data points inside the simulant literature. Chickpeas grown in Martian regolith simulant achieved 97.5% germination when seed-primed with an extract from the green seaweed Ulva lactuca, compared to 70% in a control group, the review notes. That result is real. It was obtained in fake Martian soil, under Earth atmosphere conditions, with a specific seed preparation that does not yet exist on Mars.
The gap between simulant and real regolith is not academic. Real Martian material contains reactive ferric oxides, perchlorates, and particle-size distributions that laboratory substitutes approximate but do not replicate. Apollo lunar samples produced stressed plants even with the nutrient support that no current Mars mission could provide. The review's optimism rests on a literature base that has not yet been validated against the actual surface.
The paper is a useful map of what a Martian agriculture research program would need to study. It is not evidence that the program has arrived, or that fungi applied to real Martian regolith would behave as the simulant data suggest. The authors call themselves pioneers. The data say they are still looking for a road.
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