Hi, I'm a NEW gardener!, looking for a little advice. As the title really, using a trimmer along the edges has resulted in lowering the turf that was once level with the railway slapper wall. What's the best/easiest way to fill in area like that patch and have turf grow back? There's 3 similar patches along the wall. I've been told filling the area along the edges with top soil, then sprinkle lawn seed down, and that should sort things out over time.