As I drove south on a two-lane road in central Connecticut, raindrops began to blur my windshield, and I wondered if the farm workers I was scheduled to visit might be scurrying for shelter. My destination was Imperial Nurseries in Granby. It wasn’t the human workers I thought might be daunted by a little rain, but the prototype robots that were toiling in the nursery.

When I arrived in a distant part of the 350-acre spread, two squat robots were busily moving around young juniper shrubs in plastic pots. Charlie Grinnell, chief executive of Harvest Automation, the company that makes the machines, said, “If this turned into a downpour, we’d all be running for cover, but the robots would be fine.” Harvest was conducting a two-day field test of the robots at Imperial, which could eventually become a customer.