Your youth was spent in New Haven, Connecticut, a locale that seems to have little in common with Yumi's hometown. How did you manage to evoke such precise images of Idaho farm life? What did your upbringing have in common with Yumi's? 

Well, not much. When I was growing up, in a newly developed suburb east of New Haven, trees were trees. They didn't really have names, or none that we, as children, knew. New Haven's nickname was Elm City, which, after the outset of Dutch Elm disease, was kind of sad and ironic. I guess I could identify elm trees because they were the dead ones.

Our house was in a development of identical ranch-style houses, built in the early 1950s for GIs returning from war. The developers came in with bulldozers, scraped up all the rich topsoil and hauled it away to sell, then they built the houses on the sand. When I was a child, it was a barren, lunar place. People scattered lawn seed that washed away when they watered, stuck cuttings in the ground and watched them die, cursed the developers as they bought back the precious top soil, bag by bag. My father wanted flowering dogwoods, but only a hardy species of thorny locust survived. My mother had the choice of spending money on landscaping the property or buying a raccoon coat. She chose the coat, which at the time was fine with me. You can't cuddle up to a hedge.

How did I write Yumi's Idaho landscape? I visited and fell in love with it. I visited farms. I talked to people. And then, my father came from a farming family in the Midwest, so I'd grown up with his stories, steeped in nostalgia, of how things used to be, back in the old days, when tomatoes tasted like tomatoes, and eggshells were sturdy and didn't crumple in your hand, and bread was baked fresh every day.

You've said that in your last novel, "My Year of Meats," cattle became a metaphor for a variety of concepts, including exploited women and the sexual side of human existence. In "All Over Creation," to what metaphors did farming lend itself? What made the mundane potato such an ideal choice when you selected it for the Fullers' crop?

Well, farming could be a metaphor for the entire scope of human endeavor on this planet, so there's a lot to choose from. The aspect that interested me in particular was farming as an exercise of human will over the natural environment - the ways in which, particularly in this modern age, we try to play God and control nature's every move, and the myriad ways nature outfoxes us. Farming has changed so drastically over the past hundred or so years. In the past, farmers worked in cooperation with conditions that nature set, but with the advent of large-scale chemically-based factory farming operations, that relationship of cooperation started to erode, replaced by a dangerous kind of corporate hubris.

And why potatoes? Because they are funny. They are round and jolly, and yet are a staple crop that has co-evolved with human beings. Potatoes have a rich and fascinating history, and it is to the lowly tuber that we owe a great deal of our success as a species. And because potatoes represent the American diet and seemed like an inevitable choice after "My Year of Meats." But mostly because spuds are cuter than rice or wheat or even ears of corn.

Your previous novel also revolved around the historic misuse of the synthetic hormone DES. "All Over Creation" raises questions about the issue of genetically engineered produce. Is your new novel an extension of its predecessor? Did you modify your approach to such issues when you began to write the new manuscript?

Well, an extension in the sense that I got interested in the relationship between food production and public relations during the writing of "My Year of Meats," and wanted to continue the inquiry, but I think my approach is quite different in the new book. "Meats" was a "quest" novel, and Jane was a heroine on a mission. "Creation" does not have a morally unambiguous central character, and in this world, everyone is flawed. As you point out, the DES issue was largely historic, but the issues at the heart of "Creation" are far more complex and still evolving, so it would be reductive to propose simple answers or solutions.

"All Over Creation" is told through effective shifts in time and point of view. Did this make the storyline more challenging for you to manage, or did this device provide freedom? Would such shifts have been more difficult to achieve in filmmaking, your other medium?

The simple answer: Yes.

I'm tempted to leave it at that because when I think back to the juggling I've done during the past four years, trying to get these characters and their histories to mesh, it makes me feel like an idiot. Talk about hubris! I made the classic second novelist's mistake: I thought, "Well, gee. I've written a novel so I know how to do this now. The second one should be a breeze, so why not raise the bar a bit and use multiple p.o.v.'s and expanded time frames, and then cover the natural history of the potato as well? Should be easy . . ."

It was not.

But having said that, I'm really glad I was so naïve and foolishly ambitious. I had a vision of the way the characters could mesh and intersect, and eventually they did, and I even managed to keep in some of the natural history. My editor, Carole DeSanti, is a very wise woman. I got a bit carried away with this subject, and she reined me in before I sank my story under the sheer weight of my enthusiasm. She pointed out that my readers probably wouldn't mind not knowing everything about tuber blights and famines and cloning and Conquistadors and soil chemistry, and when I questioned her, she gently reminded me that I wasn't writing Moby Dick, and anyway Herman Melville would never have gotten a book contract in this day and age of publishing. This is why writers need smart editors who care.

Performance protests such as those launched by The Seeds of Resistance are common in some parts of America, particularly in the Midwest. Did you have any first-hand experience with their brand of information dissemination?

I don't know if they are common or not. Maybe not as common as they should be, although I don't condone violent action of any kind. I haven't had a lot of first-hand experience with direct action protests, but I know people who do. Everyone has his or her own style of social participation, and mine is primarily through my writing and speaking.

Were you purposely ambiguous about the perpetrator of the tragic event near the end of the novel? Was it important to you to propose the possibility that the destruction was accidental?

Good question. Yes.

Are you a gardener? What did your characters teach you about "growing" a novel?

I'm not a gardener, but my husband is. He is an obsessed gardener. He gardens night and day. He gardens the way I write. He’ll grow anything, but he has a special fondness for cacti, which he grows from seed. Do you know how long that takes? And not only that, he collects his own seeds, which means he has to hand-pollinate each of the cactus flowers first. He collects the pollen by making miniature dunce caps that fit over the top of a blossom. When the pollen collects like dust on the sides of the cap, he takes a tiny sable paintbrush and transfers it to another flower and waits for it to produce seed. These cactus seeds are tiny and very slow to germinate. Once he plants them, he waits. And waits - you can imagine the suspense - until eventually a tiny green nub pokes through the sand. He has, in his collection, ten-year-old cacti the size of a worn-down pencil eraser. Ten years. Compared to that, novels are quick 'n easy.

But in the same way that a gardener learns from his plants, a writer has to let her characters teach her. It's not easy. Here's another example of hubris: You start a novel feeling like God, populating your imaginary world, and you feel enormously powerful and in control, but years later, as the novel comes to a close, you realize that you have mysteriously become enslaved to your characters and their whims and their ways. It's hopeless, really, and the only answer is to forgo control and let the characters lead you.

How did you balance the novel's humor with its weighty issues? How did you keep the polemical aspect of the plot from dominating the novel's tone?

I guess I don't see the humor as being separate or apart from the weighty issues. Weighty issues are quite funny, in addition to being quite serious, and thank goodness for that! Were that not the case, how could one bear to tackle them?

I don't think of my novels as didactic or polemical. I certainly don't write them in order to "teach" or to "convert." That's totally not the point. I write in order to initiate an inquiry, primarily my own, and if the reader's spirit of inquiry is sparked by my puzzles and enthusiasms, well, that's great, but it's almost a by-product. However, having said that, since I do publish, I have to cop to the fact that I hope readers are sparked, and that good things will come from our efforts.

Many of your characters are at odds with one another. Were you able to divide your loyalties equally among them, particularly when it came to Yumi and Cassie?

When I write a character, I inhabit that character. When I was a little girl, about six or seven, I remember realizing, with a deep sense of shock, that I was forever trapped inside my skin, and I would never be able to experience the world from inside another's. This fundamental human limitation struck me as profoundly tragic and unsettling. What if my brief six or seven years of experience were entirely subjective, and my cognizance of the world were mine alone? What if what I saw as green, you saw as red? How would I ever know otherwise? Suddenly the world felt like such a lonesome, uncertain place, and I remember wishing that I could slip magically inside someone else's body and look out their eyes, for a minute or even a single second. If I could do that, I would know. I'm sure I started to write in order to combat this terrible loneliness.

Now . . . what was the question? Oh, right. Because I do inhabit my characters to such an extent, I've never had a problem with divided loyalties. My main problem is that certain characters, like certain people I know, are very pushy and try to take over. Generally it's the character that most resembles me, and the trick is to make her shut up.

Yumi's name is ideal for her character. What inspired you to call her Yumi?

You. Me. And the inevitable mispronunciation,"Yummy," which allowed me to pay tribute to one of the finest songs of the Seventies.

What's next from you - another novel, or a film?

I wonder if I'll ever make another film. It's so darn hard. I hate to be lazy, but it's easier to write, and a lot cheaper. However, having said that, I'm tempted to make another film about my mother. My husband and I take care of her. She has Alzheimer's now, and while that is very sad, she also happens to be very funny. There. You see? Dementia is certainly a weighty issue, but it has its humorous sides, too, mostly having to do with the way my mother constantly trips me up. But realistically, I think I'll write another novel. I have a couple of story ideas and a passel of characters inside my brain, fighting like cats in a sack. It'll be interesting to see who emerges first.

• excerpt from All Over Creation
• readers' guide