As humans set their sights on building a sustainable foothold on Mars, one of the hardest problems is deceptively simple: how do you grow food on a dead, toxic world? Hauling soil and fertilizer across roughly nine months of space is too costly and too fragile to sustain a colony, so any serious plan for the Red Planet depends on crops that can thrive in Martian dirt. A pioneering greenhouse study from the Netherlands suggests that an old farming idea — intercropping, long associated with ancient Maya farmers — could become part of the answer, though the real findings are more nuanced than a simple success story.
Intercropping means cultivating different plants together so their complementary traits help one another, optimizing scarce water and nutrients. Researchers at Wageningen University & Research applied that idea to space agriculture for the first time, in a study led by astrobiologist Rebeca Gonçalves with co-authors Dr. Wieger Wamelink, Peter van der Putten, and Dr. Jochem Evers. Their paper, “Intercropping on Mars,” was published in the journal PLOS ONE on May 1, 2024.
Cherry Tomatoes, Peas and Carrots in Fake Martian Dirt
The team grew cherry tomatoes, peas, and carrots in three soil types — a NASA-developed “MMS-1” Mars regolith simulant described as a near-perfect physical and chemical match to real Martian soil, plus potting soil and sand for comparison. Plants were grown either mixed together (intercropping) or separately (monocropping), with rhizobia bacteria added to the peas to help fix nitrogen, and the greenhouse’s gases, temperature, and humidity tuned to mimic conditions inside a future Martian greenhouse.
The standout result was the tomato. Grown alongside the other crops in the simulant, cherry tomatoes produced roughly double the yield of tomatoes grown alone, with more and bigger fruit, earlier flowering and maturation, and thicker stems. Researchers believe the tomatoes benefited from their pea neighbors, which — with the help of soil bacteria — pull nitrogen from the air into a usable nutrient. “We had expected the peas to grow the best but the opposite turned out to be true. The tomatoes grew the best,” Wamelink noted.
The Honest Result: A Mixed Harvest, Not a Triumph
The tomato win came with real caveats that are central to the science. In the harsh Mars regolith simulant, intercropping was beneficial for tomato but mostly detrimental for pea and carrot — carrots yielded less biomass, and peas showed little change — leaving the system with an overall yield disadvantage versus monocropping, a total relative yield of 0.93. The culprit was biology: rhizobia failed to form the root nodules needed for nitrogen-fixing in the regolith, likely defeated by its high pH, compactness, and nutrient deficiencies. The tall tomato and pea plants also out-competed the carrots for light. As Wamelink put it, the tomato profited from the peas but the carrot “most certainly did not.”
Crucially, the picture flipped in sand, where better soil conditions allowed effective nodulation and intercropping clearly outperformed monocropping, with a relative yield of 1.32. That contrast is the real takeaway: with targeted improvements to Martian regolith to support nitrogen-fixing bacteria, intercropping shows genuine promise for feeding future colonies.
Toxic Soil and the Perchlorate Problem
Even an optimized intercrop has to contend with what makes Martian soil so hostile in the first place. Real regolith carries toxic perchlorates at concentrations far above Earth’s, and it lacks organic matter entirely. One avenue researchers are weighing is using microbes to break down those perchlorates and detoxify the ground before planting.
Why This Matters Back on Earth
Although the work targets Mars, its payoff may land closer to home. As climate change degrades soils and makes rainfall less predictable, techniques refined for the worst dirt imaginable could improve crop resilience in arid and depleted regions on Earth. Gonçalves has stressed that whatever is learned about farming on Mars can be translated directly to farming here. The broader push toward off-world agriculture is already underway, with companies developing autonomous growing systems for commercial space stations, and NASA targeting crewed Mars missions in the 2030s. Wamelink himself now leads a company, BASE, developing lunar and Martian greenhouses.
“Since this is pioneering research, where it’s the first time that this intercropping technique is applied to space agriculture, we really didn’t know what to expect,” Gonçalves told reporters. “And the fact that it worked really well for one out of the three species was a big find, one that we can now build further research on. Now it’s just a matter of adjusting the experimental conditions until we find the most optimal system.”
For more space and science coverage, explore theAegisAlliance.com’s Science and News sections. The road to a self-sustaining colony will not be paved by any single experiment, but pairing an ancient planting strategy with modern crop science is exactly the kind of out-of-the-box thinking that a future on the Red Planet will demand.
