Welcome to this forum, first of all. It depends on the view you want. If it's for distance, I'd use procedural (fake) grass (search for fake grass or procedural grass), with population(s) of the internal grass a bit closer by. For really close-up I'd add better grass objects, but you need to populate a few types and have them overlap for a varied grass layer.
For very short, more distant grass, a fake stone based procedural grass will do nicely most of the time. Also depends on how big you need to render of course.
I hope this gives you some idea.