July in the Merrimack valley is thick and bright, and by seven in the evening the heat lets go all at once and the lawns in Groveland go a deeper green than they were at noon. Santos Irrigation Services keeps those yards on an even keel through the hard weeks — mowing high enough to hold moisture, trimming clean, feeding and seeding when the season turns kind again. Anyone who mows here in midsummer learns to read a lawn quickly: where it burns first, where the shade saves it, which corner always stays soft. Getting a property through August still looking green is a genuinely good day's work. Come September the whole town seems to exhale, and the grass does too.