Come July in Yarmouth the whole town smells like fried clams and cut grass, and the lawns out along the way to Cousins Island are being mowed on a tight weekly clock. Organics Lawn and Landscape Inc. keeps that clock — mowing, trimming, edging, and the ongoing maintenance that holds a lawn even and dense through a salt-air summer. Spring begins with a cleanup that lifts sand and thatch off the turf; autumn ends with one that clears the last leaves before the bay wind carries them somewhere else. Casco Bay light runs long and low in September, and it shows every stripe on a mown yard. That is the part worth doing well.