Toward Cisco and Hummock Pond the soil is sand under a thin skin of loam, and a dry July will pull the green right out of a lawn. TNT Lawn Sprinklers looks after lawn irrigation on Nantucket — waking systems up in spring, keeping coverage even through the hot weeks, and putting them to bed before the first hard freeze. Even watering is quiet work: heads adjusted, dry corners chased down, no puddles and no brown crescents anywhere. The proof arrives at dusk, when the sprinklers come on across a lawn that held its color all August. Out here at the edge of the ocean, green in high summer is something you build.