It's been 10+ years since I based a
40k model, and back then I used the old fashioned green flock.
This is my prototype, for my Dark Angels:
Half the base is covered in tiny pieces of broken up cork, and other other side with sand (some of it large pieces).
Grey drybrushed over black, followed by a lighter white drybrush.
My eyes aren't brilliant with certain colours, but the grass is supposed to look somewhat burnt/dead.
If you can see any brown among the "rocks", those are just the parts I missed with the undercoat, since this is only a rough prototype.
I would appreciate any advice.