live in the city and I'm luck enough to have my own driveway. City driveways have that strip that runs down the middle so that grass can grow in between the concrete edges. But with the shade that covers the yard, there is no grass, only dirt that runs downhill when it rains, slowly leaving a 2-3 inch drop from level with the concrete. The concrete edges are like a sidewalk, about 5 feet long and two wide.

What are some ways to best fill in this dirt area?