For a few September mornings the balloons go up over Dansville and the whole Canaseraga valley becomes a floor for them. CHC Solutions works that valley the rest of the season — mowing, trimming, mulching and the steady upkeep that keeps a yard from getting away from the people who own it. The hills stand up fast on both sides here, so the lawns are terraced and odd-shaped and no two of them mow the same way twice. Air off the Stony Brook ravine keeps things cool into June and the grass growing hard straight through it. A yard finished before noon on a bright Dansville day is a small and complete thing.