EVERY TIME ROSA GARCIA’S FAMILY* relocates—pursuing the latest harvest opportunity, from Florida’s winter citrus crops to the autumn vegetables of Michigan—she must negotiate a strange town and, often, a strange school. Now a tenth-grader, Rosa encounters the same cliquish cruelty all teenagers face, but magnified a hundredfold by virtue of her status as the new girl, the one with brown skin, the one who appeared midsemester and may soon vanish. “Lunch is the worst,” the 16-year-old says, “because you have no friends, nowhere to sit, no idea where you’re going next.”

Rosa’s parents, Hector and Angelina, crossed the muddy waters of the Rio Grande in 1995 with their two eldest children, and spent a few months building fences on Texas ranches before settling into the East Coast migrant-farmworker circuit. Today, all seven Garcias—including Rosa and two more U.S.-born kids—log hours picking produce, though compensation tends to be calculated at a piece rate instead of by the clock: A 32-pound bucket of tomatoes might bring $1. “Agriculture is very heavy work,” says Hector, 45, through a translator. “We toil from sunrise until our bodies can’t take any more.” A good day yields $60, just enough to keep food on the table and gas in the car.

And that’s assuming the ranchero, or farm owner, pays. After several weeks at one Georgia tomato operation, Hector still hadn’t received a cent from his employer, who no doubt banked on the improbability of an undocumented itinerant to stay put and push for past-due wages. “We had to move on and follow the harvest,” Hector explains. “We couldn’t keep waiting.” The family was also evicted, and wound up homeless with less than $50 to travel several hundred miles to Tennessee. “It was incredibly difficult,” he recalls. “We had to stop and and work along the way.”