This is my work-in-progress approach to "normal" green grass vegetation on dirt surfaces. I use Army Painter Brown Battleground texture and Army Painter Battlefield Basing Glue for convenience/availability.

Preparing the base

1. Use an old brush to dab PVA glue to the surface of your base.
2. Immerse the mini's base underneath the desired battlefield texture. (I use Army Painter Brown Battleground texture.)
3. Once that glue dries, create a 1:1 mixture of PVA glue and water.
   Note: the consistency of the glue should be runny like that of milk.
4. Spread your 1:1 glue to water mixture on top of the base of material glued earlier using an old paint brush. Once dry, the glue will appear in a clear coat on top of the basing material, allowing for paint to adhere and not flake off.

Brown ground

1. Apply a layer of Oak Brown to the base surface

Grass

1. Randomly dab a light amount of PVA glue where you want grass to appear
2. Submerge your base while the PVA glue is still wet into your desired artificial grass. I use Army Painter Battlefield Basing: Grass Green for static grass.
3. Gently tap the miniature or base to the side of the static grass container to remove excess grass. Let it dry and you're good to go!