They farmed that lawn for more than two decades before moving here, to do the same thing, in 1995.

Ms. Gussow had gone back to school in 1969 to earn a doctorate in nutrition at Columbia University, at a time when nutrition was all about vitamins and chemistry, not how food was grown and where it came from. She began connecting the dots between what Americans were eating and how that food — be it factory-farmed chicken or Twinkies — was produced.

She created a legendary course, Nutritional Ecology, which she still teaches today, with a former student, Toni Liquori, who as director of School Food Focus, a nationwide program, works with school districts to buy more healthful, locally grown food.

Because Ms. Gussow dared to talk about energy use, pollution, diabetes and obesity as the true costs of food, she was initially viewed as a maverick crank, but her connections inspired the work of people like Michael Pollan, whose book “In Defense of Food,” echoes many of her revelations.

“She has been a powerful influence on the food movement,” said Mr. Pollan, adding that he admires her “clarity of thinking” and her ability to cut through complex issues to the simple truth: “We all know nutrients are important,” he said. “But Joan says, ‘Eat food.’ That’s the kernel of ‘In Defense of Food.’ ”

Ms. Gussow’s thinking, like Mr. Pollan’s, has always been grounded in the garden.

That muggy morning, as temperatures headed for the high 90s, we dumped the bags of soil near the boardwalk, where, only a few feet away, mallards were paddling peacefully in the quiet water. It was hard to imagine that in March a storm had brought the river surging over the boardwalk, tearing up its boards and pilings, ripping raised beds out of the ground as it moved toward the house, burying the long narrow garden — 36 by 100 feet — under two feet of water.