September in Sheepshead Bay brings cooler air off the water and boats still heading out past the Emmons Avenue docks. Cambridge Lawn Care Services works the streets behind that waterfront, where salt air is hard on a lawn and steady cutting is what keeps it thick. Mowing, edging along the drive, trimming hedges back off the walk, clearing whatever the wind piles into the corners. The result is a small front yard that looks cared for from a passing car and better still from the top step. Lawn cutting and yard upkeep around Brooklyn.