CASCO BAY, Maine — I do not agree with Samuel Johnson that remarriage is the triumph of hope over experience. That dubious triumph belongs to the gardener, not the bride and groom.

By the time the seed catalogue comes through my urban door slot in midwinter, I have forgotten last summer's yellow wilt, the invasion of the monster tomato worms, and the enemy battalions of weeds. I have a dim memory of the bittersweet vine — bane of my existence — or of my own slacker's performance as a farmer. I pick and choose seeds as promiscuously as a rogue bachelor on Match.com.

So I am here again, having arrived on the island with an excess of seeds, plants, and expectations. The chives and the rhubarb, hardy perennials, which can do without my ministrations, greet me the way year-round islanders welcome back the fair-weather summer people.

I pull out the hoses and sort out the lettuces, turn over the soil and proudly sow straight lines of arugula and leeks, carrots and chard. It's as if I didn't know that the order of Memorial Day would become the chaos of bolting lettuce and overgrown beans by Labor Day.

My only claim to landed gentry was my grandmother's city grocery store. Nevertheless, I have been growing food for 30 years.

It all began with parental virtue. It seemed to me that we expend so much energy around sex ed, telling our children where babies come from — and so little time on food ed, telling them where lunch comes from. I wanted my daughter to know that a carrot was the root and a tomato was the fruit, that food came from the earth rather than the supermarket. Now I offer this biology class to my grandchildren.

Of course, it is not just virtue that has led me to the land. It is also vice. It is arugula envy, asparagus gluttony, green bean chauvinism and the pride that makes me refuse to eat the red things in the store mislabeled "tomato."

And I have yet another reason to recommit to my own patch. I am a convert to the idea that we can think global, eat local. Hoe in hand, we just might make a small repair in our world.

Over the past few years, a combination of environmentalists and foodies and small farmers is finally convincing civilians — all of us who eat for a living — that the way we eat affects the world we live in.

I have seared into my memory the fact that every item on my plate has traveled an average of 1,500 miles to get there. Some 85 cents of our food dollars go to processors, manufacturers and transporters that make up the food industry, a phrase that used to be an oxymoron.

This year's proselytizing comes in a highly digestible form. In her book, "Animal, Vegetable, Miracle," Barbara Kingsolver tells the engaging story of the year her family ate locally, mostly food they raised themselves. "Transporting a single calorie of a perishable fresh fruit from California to New York takes about 87 calories' worth of fuel. That's as efficient as driving from Philadelphia to Annapolis, and back, in order to walk three miles on a treadmill in a Maryland gym," she writes, "Pardon me while I ask someone else to draft my energy budget."

We have also become increasingly aware of the holes in the food safety net. The same global economy that gives us raspberries from Chile in January also gives us melamine from China in our pet food. Meanwhile, our food policy supports all the processed food that fills the center aisles of the supermarket.

Michael Pollan, author and a one-man consciousness-raising group, says of the massive federal farm bill that is now up for renewal, "the system is rigged to make the most unhealthful calories in the marketplace the only ones the poor can afford." Until now, he writes, our policy "essentially treats our children as a human Disposall for all the unhealthful calories that the farm bill has encouraged American farmers to overproduce."

Having grown up in an apartment, I know my victory-over-sore-muscles-garden is my luxury. After starting my day with coffee from Sumatra and sweetening my native rhubarb with sugar from Louisiana, I have no false sense of self-sufficiency. And I have no illusions of thrift in my heirloom tomatoes.

But reading the label on my seed packets this morning, I count the days until the carbon footprint on my plate shrinks and the taste expands. As someone who spends most of her time working for the money to buy the food, I am briefly a collaborator with the earth. In a world of global warming and global warnings, these are moments when hope is itself a triumph.

Ellen Goodman is a columnist for The Boston Globe. Reach her at ellengoodman@globe.com.