The surface of Mars is a thin layer of iron oxide rich dust overlying a volcanic basalt crust. Soil on Mars is simply material fine grained enough to be affected by wind. It lacks any organic properties that make Earthly soils actually soil. This makes sense, because at press time there is no known life on Mars. These soils are rich in sodiums, potassiums, magnesiums and chlorines which, for the most part, are good for plant growth.
However, we all know the saying “everything in moderation” – and this applies to the elemental composition of Martian soil just as much as it does to how many cookies you can eat in a sitting.
Martian ‘soil’ contains toxic levels of chlorine (in perchlorate compounds) which, when replicated on Earth, displayed stunted development of most plants grown in it. The chlorine toxicity, the iron oxide richness, freezing temperatures and constant barrage of UV radiation create a tough time for life to grow in the soil.
However, there are some bacteria that could quite possibly live off the toxic environment (could become the common soil bacteria that creates a healthy ecosystem) and experiments did indicate some plant life was capable of taking in the chlorines and effectively cleaning the soil of it. This does not solve for the increased UV radiation or the cold weather, but this could be simply remedied with human-made habitats.
If most of the stressors above are properly countered, enriched the soils can become farmable. Regolith simulants like the Mojave Mars Simulant by The Martian Garden (based off the work of NASA and JPL conducted with the Phoenix lander missions) provide scientists insight of what they might encounter when they reach the surface.
It’s not all bad news from Mars, either, because the reduced gravity could potentially have a positive effect on plant growth. Soils could hold more water and hold it longer, because Martian gravity is about 38 percent of Earth’s.
In short, growing plants on Mars is certainly an involved process, but not outside the realm of possibility… So yeah, Mark Watney could’ve done it.
Let’s grow plants on Mars.
This page was written by our resident astrogeology expert, Hudson Koch. Hudson is a geophysicist who is interested in planetary science.