A British cannonball from the Battle of Ridgefield in 1777 is still lodged in the corner of Keeler Tavern on Main Street, and the street around it is lined with old shade trees and broad front lawns that have to get through dry Augusts. American Irrigation Systems handles the water side of lawn care in Ridgefield, setting yards up with irrigation so the grass gets what it needs when summer turns stingy. Before dawn, while the town sleeps and Great Pond lies flat under mist, sprinkler heads rise, hiss across the turf and sink away before the dew burns off. A Ridgefield lawn may have full sun out front, maple shade along one side and a slope behind, and the watering has to suit each part. Come late August the payoff is grass that stays deep green while the roadside verges have gone to straw.