Now we need to paint the ground.
I like to start out with a good Burnt Umber as a base for most of my soil. I use an artist acrylic that I purchased from the book store. Burnt Umber is a very common artist color, so use your favorite brand.
Thin the paint down considerably before applying it to the sand. If it's too thick, it will clog the grit of the sand, and make drybrushing much more difficult. If it's thin, you can be generous with the paint.
Allow this to dry overnight.