Answer: It is potentially possible to grow grass on Mars, but is most likely to succeed with the help of humans.
Let us explain.
Can You Grow Grass on Mars? (Explained)
Presence of Nutrients
We know what grass needs to grow here on Earth, and many of the macronutrients and micronutrients necessary to support plant growth do exist on Mars.
This nutrients (macro and micro) include oxygen, calcium, sulfur, iron, chlorine, zinc, copper, potassium and more.
We’ve been able to detect some of the nutrients in the soil itself (because we have rovers there!)
We have also detected some of the nutrients in Martian meteorites.
However, the presence of the nutrients does not mean that an astronaut can hope off a ship and drop some seeds straight into the soil as he/she plants her flag.
First, it is important to note that the soil on Mars varies from place to place, as does the soil on Earth.
In some areas, the composition of the soil would be insufficient to support the growth of grass without the addition of fertilizer, or the transportation of Martian soil from other locations (likely both).
Second, like Earth, the temperature varies on Mars.
While the temperature on Mars averages a chilly -80 degrees F, this average does not tell the whole story on the surface conditions of Mars. This is just an overall average.
In certain areas (like the poles), the temperature falls to -200 degrees F or even colder during Martian winters.
Obviously, the varieties of grass that grows on Earth cannot survive at this temperature.
In other areas, during Martian summer days, the temperature can get as high as 70 degrees F.
This temperature (or even something close to it) would be warm enough for grass if it were that warm long enough and consistent enough for the grass to sprout and grow.
There are many different kinds of grass.
Certain grasses thrive in warm weather conditions (and need the heat to germinate), while others can survive happily in cooler temperatures.
However, even though grass can survive cooler temps (or even a freeze), grass seed needs warmth and moisture to germinate.
During the nights when the grass was on the side of Mars facing away from the sun, due to the thin atmosphere and distance from the sun, it would probably be too cold for grass to thrive.
This is even the case in areas where it was warm enough during the day,
Third, while there may be water ice on Mars, seasonal water flows, and vapor in the atmosphere, the water situation on Mars is not certain.
The water on Mars (to the extent it exists) might not be good for grass.
We don’t know what minerals or other elements/compounds are dissolved in it, and it is probably not consistent.
But without water, grass seed will not germinate.
Fourth, the Martian atmosphere is significantly thinner than Earth’s atmosphere.
It is composed of mostly carbon dioxide, nitrogen, and argon.
There is very little oxygen, just .13%, compared to Earth’s atmosphere, which is over 20%.
While plants can generate oxygen through photosynthesis, they often need additional oxygen in the air or soil to survive.
We also know that the atmospheric pressure in Mars is much less than it is on Earth.
This can impact plant growth negatively, though studies have shown that plants can survive at lower pressures.
Grass Growth on Mars
It seems like it could be possible to grow grass on Mars.
The nutrients plants need to grow are there.
Water is there.
Carbon dioxide and oxygen is there.
There are places where it is warm enough (sometimes).
But most likely, it would take humans with some kind of greenhouse structure to make it happen, with the humans balancing the nutrients in the soil and air, providing the grass with the right amount of water, stabilizing the air pressure at optimal levels, and keeping it consistently warm enough for the seed to germinate.
Given these facts, while it is theoretically possible, it seems really unlikely that scattering grass seed around without an intentional plan to support the growth of the grass would produce any positive results.