At six on an August morning, Babylon lawns are still wet with dew and the day has not decided how hot it will be. Dean's Sprinkler Service, Inc. moves through that early quiet doing lawn work — mowing, trimming, edging, feeding, and clearing beds when the season flips. Grass out here lives on the narrow margin between the humidity coming off the water and the sun that follows it. Getting a lawn to hold its color through a Long Island summer is mostly attention, repeated. The result is a yard that looks unhurried, which is the whole trick.