Sidewalk landscape

I have 2 sidewalks i created, 1 has 2 elements and the other has 0. What im trying to do is create a sidewalk with grass. For one of my sidewalks i added 2 materials to it which is concrete and grass. For the other sidewalk it has no elements all i did was add a concrete material to it. The sidewalk that doesnt have any elements i was going to vertex paint grass or grass tool. Am i better off just doing 2 elements?

i beleive so