Indeed. But without an atmosphere to shield the planet from deadly radiation, nothing is going to happen. The creation of an atmosphere is a kind of ‘’ankle bone connected to the leg bone’’ thing. You need a molten iron core to generate a magnetic field which creates and atmosphere and contains it. Once the inner core cools down, the magnetic field weakens and the atmosphere begins to evaporate. Once the core has cooled to the point where it cannot sustain the magnetic field, it’s game over.
Exactly and soil is just one tiny link in a whole ecosystem. The primary problem is how to create a planet enveloping magnetic field to help protect your gains.
Discounting that I think I would start by putting an inflatable dome over a crater in a low lying area just to see what kind of temperature can be attained by normal solar heating and if any moisture migrates out of the soil. You would have to heat the dome at night and condition the soil but that’s the way I would start.
I did find an article about growing things in lunar and martian soil analogs. http://www.spacesafetymagazine.com/spaceflight/space-food/wageningen-ur-study-possibility-plant-growth-mars/
To me its all interesting to ponder but I have unlimited imaginary funds.
Ignorant question alert: would it be (remotely) possible to reinvigorate Mars’ core by starting some sort of nuclear reaction there?