September on the south side of town, out toward Fossil Creek, is when Fort Collins lawns catch their second wind: cool nights, low sun, soil finally willing. Barefoot Lawn Care and Aeration works that window — pulling cores, mowing, overseeding into the openings, cutting the edges back to a line. The yard looks briefly untidy, plugs scattered like a field after harvest, and then it thickens in a way that carries all the way to spring. Clay ground under Front Range sod packs hard by the end of August, and opening it up is the least dramatic and most useful thing anyone does for a lawn. Come the following June nobody remembers the cores; they just notice the grass.