>>212683032Anon you don't really need to plant your crops in dirt.
You'd just need a local water source, and chemicals like nitrates, and you just use aero/hydroponics.
Really though, once you get out of a gravity well there's no good reason to hurry to get yourself stuck in another one.
If you can get large numbers of people off the planet, and keep them in space indefinitely, just do that. You can exploit resources in orbit to build habitats that can harvest resources and manufacture more habitats.
You've got everything you need in orbit.
The only reason to go down to a planet ever again is for scientific reasons.
Though a cool thing about mars is the gravity is just low enough you could build a space elevator with contemporary materials.