Organic gardeners know the mantra “feed the soil, let the soil feed the plants.” Healthy soil leads to plants that are not only more vigorous and resilient but also more nutrient-dense. My guests this week, “What Your Food Ate” authors David Montgomery and Anne Biklé, explain that when we take care of the land, the land takes care of us.
Anne, a biologist and science writer, and David, a geologist and professor of geomorphology at the University of Washington, are married and live in Seattle. Anne practices regenerative gardening and focuses on the connections between people, plants, food, health and the environment. David is a MacArthur Fellow who studies the effects of geological processes on ecological systems and human societies. “What Your Food Ate: How to Heal Our Land and Reclaim Our Health” is their most recent book, building on a series of books they have written on soil health, microbiomes, and farming — “Dirt: The Erosion of Civilizations,” “The Hidden Half of Nature” and “Growing a Revolution.”
David Montgomery and Anne Biklé are a husband-and-wife, geologist-and-biologist writing team.
Photo Credit: Saxon Holt
“What Your Food Ate” explores how the roots of good health start on farms. Anne and David bring to the forefront evidence from recent and forgotten science to share how the health of the soil ripples through to crops, livestock and, ultimately, us.
“We’re always happy to talk about connections between what’s going on in the natural world around us and how that influences the way we think, the way we live, and of course, what we’re eating,” Anne says.
“It is kind of an odd background that we have, with me being a geologist, Anne being a biologist, and us sort of thinking about and writing about the soil,” David says. “Because the soil really is where the biology meets the geology.”
The Real Dirt on Dirt
David explains that geomorphology — the study of how erosion shapes landscapes — is “the geology of the here and now.”
“My training is in biology and natural history and environmental planning, and I also am one of these people who’s interested in connections between different things,” Anne says.
She notes that living in Seattle, rivers and streams are a big part of their local landscape. She previously worked on salmon habitat restoration projects by figuring out “how to reconnect rivers to their floodplains, working with landowners, getting native plants back on the river banks.”
Anne loves hands-on work and being outside, she says, seeing and thinking about how things work, and what humans’ role is in holding this place together and keeping it going.
She has a case of what she calls “plant lust,” which she describes as connecting with a plant and having to have it. “This, I think, goes way beyond me, and it goes way back in human evolution as well,” she says. “Everyone has an inner plant lust. I think it’s just hard to keep in touch with that, and it’s hard to express that sometimes in our modern world.”
We are all connected to the earth in some way, and we all discover that at some point in life — some sooner than others. But eventually, we all realize it.
David says he’s been very interested in how natural ecosystem processes have influenced human societies throughout history. “But I’ve also been interested in how people have influenced the land throughout history, and in particular, how people have degraded soils and how soil erosion has shaped the course and fate of literally civilization after civilization around the world.”
A before photo of Anne Biklé and David Montgomery’s side yard, with soil the color of a beach sand and filled with rocks. Glacial till is about a foot down.
Photo Credit: Anne Biklé and David Montgomery
Lessons on Dirt from a New Garden
Around the time that David published his first popular book, 2007’s “Dirt: The Erosion of Civilizations,” he and Anne bought a house in North Seattle. Anne immediately wanted to put in a garden.
“We realized soon after we bought that house that we had crap soil,” David says. “We pulled off six inches of tangled-root lawn that had been there for probably literally about a hundred years. There wasn’t a single worm that crawled outta that khaki-colored dirt.”
Anne set out to fix the soil at the same time that David was writing a book, titled “Dirt,” about how societies had destroyed their soil. He says that right outside their back door, she transformed a biological desert into a burgeoning fountain of life a number of years later.
“We saw the soil change as a result of the gardening practices that she was implementing, and there’s parallels with what goes on in agriculture that relate to the sustainability of human societies,” David says.
“In a way, ‘Dirt’ was a problem statement of trying to understand how the way that people treat the land affects the way the land treats their descendants,” he says. “And there’s a very real story there that unfolds from society after society. And the bottom line in that book is quite simple: Societies that don’t take care of their land don’t last.”
“Dirt: The Erosion of Civilizations” explores how the way that people treat the land affects the way the land treats their descendants.
Photo Credit: University of California Press
Anne restoring fertility to their yard at the same time that he was writing a book about how societies had destroyed their land motivated both of them to look into what was driving the rapid rebuilding of soil fertility.
“That led us into the world of microbes, and the way that the fungi and the bacteria in the soil partner with plants and can build healthy, fertile soils,” David says.
That understanding led them into writing “Growing a Revolution,” taking the lessons they learned in Anne’s garden and determining how they could be applied on a global scale.
“The principles of the regenerative gardening that Anne was using in our yard are really quite parallel to the principles of regenerative farming,” David says. “That was a very eye-opening and positive — an optimistic conclusion.”
“What Your Food Ate” addresses how the treatment of soil in farming practices affects what gets into our food and, in turn, our health. “That was a real eye-opener for us as well,” he says.
“This series of books really goes through our learning experience of how to connect all these dots. I didn’t imagine we’d write four books on soil when I wrote the ‘Dirt’ book, let alone that I’d be brave enough to write two books with my wife,” David says.
Anne says “The Hidden Half” is about their insight into a cure for soil.
“A lot of that revolves around microbiomes, these communities and populations of bacteria, fungi, and other microbes that are indigenous to a place and to their host,” she says.
When David looked at a range of farms and their practices, they wondered, “Do you think this has something to do with the quality and nutritional density of food?” Their answer was a resounding “yes!”
“Most of the plant microbiome is in the roots, and there’s all of these exchanges going on ceaselessly, nonstop, and it has been that way since the beginning of these first intrepid plants that came onto land some 400 million years ago,” Anne says.
“The Hidden Half of Nature” concerns a cure for soil through encouraging a healthy soil microbiome.
Photo Credit: W.W. Norton
Diet Changes
“We’re eating different things now than we did a hundred years ago, or 5,000 years ago, or 10,000 years ago,” David points out. “We’re eating a lot more grains since the 20th century.”
Raising more grains was the answer to the problem: How do we feed the world?
“Our ancestors didn’t eat a lot of grains before the dawn of agriculture,” he says. “So there’s changes in what we’ve been eating, but there’s also changes in what’s in what we’ve been eating.”
They looked into how farming practices affect what gets into our food in ways that affect human health.
They identified the four areas affected, what Anne calls the Fab Four: phytochemicals, or chemicals the plants make; vitamins and minerals, otherwise known as micronutrients; metabolites that the microbiome creates that plants then take up; and the fat balance in meat and dairy, particularly omega-3 and omega-6 fats.
“The medical and the agricultural literature rarely intersect,” David points out. He says that is a big reason why they wrote the book. They wanted to demonstrate how the way we farm ultimately affects human health.
Most studies look at differences in organic farming and conventional farming in terms of the macronutrients that our bodies need a lot of, such as carbohydrates, proteins and basic elements like potassium and magnesium, he explains. “There’s less evidence that farming practices have a big impact on them.”
People need macronutrients to survive, but to stay healthy, there is more that people need, albeit in smaller quantities: micronutrients, phytochemicals, microbial metabolites.
David says there is solid evidence that how we treat the soil has effects that ripple into what’s in the crops and animal-based foods that we eat.
Anne notes that standard nutrition and standard medical practice hearkens back to a time in human history when famine was ever present. Calories to fuel growth was the priority.
“For most people in most places in the world today, we do have enough to eat,” he says. “Of course, it’s not everywhere. But for most of the world, that is the case.”
With all that biomass available to feed the masses, Anne and David wanted to get into the question of how do we ensure that the food is providing all the tissues, organs and cells in our bodies with what they need to grow from infant to adulthood to old age in good health.
With the exception of animal fat balances, the Fab Four have no caloric value, Anne points out. But they do ensure “the normal functioning of human biology in all of that complexity.”
Insufficient levels and inappropriate compositions of the Fab Four in our plant and animal foods are shorting human biology on what it needs to just function normally, she says.
Farmers are paid by the bushel or by the liter or pound, she points out. They aren’t paid for nutrient density, so the financial incentive does not align with human health needs.
She wonders how we can compensate farmers for practices that ensure that we’re getting the right levels, in the right mixes, of things that dovetail with human physiological processes.
“Two of the key things that a lot of these phytochemicals and micronutrients do is that they act as antioxidants and anti-inflammatories when they get into the human body,” David adds. “And when you look at maintaining health over the long run, those kinds of compounds are really beneficial, because inflammation and oxidative damage are really at the root of most of the common chronic illnesses that have exploded in prevalence in the latter half of the 20th century — right as our agricultural system changed.”
Post-World War II, when many chemicals became available to farmers for the first time, there were people like J. I. Rodale out there saying “healthy soil equals healthy plants, equals healthy people” and “how we treat the land affects how it, in turn, treats us.”
Prior to those conventional ag chemicals coming along, we were feeding the soil with manure and natural ingredients and organic material that was nutrient dense.
Photo Credit: W.W. Norton
How Regenerative Agriculture Is Reversing Bad Trends
Anne says the most profound impact on soils is what farmers call inputs. The input that modern ag relies on most is synthetic nitrogen fertilizer.
“It’s in a form that plants can quickly take up,” she says.
Applying synthetic, soluble nitrogen fertilizer has almost immediate results in terms of growth.
“Plants are not just these dumb sedentary creatures stuck in the ground,” Anne says. “They are efficient. They are expert at forming symbiosis with their microbiome.”
When there are nutrients freely available in the form of synthetic fertilizer, plants change their behavior, she says. “That nitrogen is in a readily accessible form. It is not unlike processed carbohydrates in the human diet.”
With so much nitrogen around, plants start to lose the symbiosis that they built with the microbiome in the soils.
The plants stop sending out root exudates — proteins, fats and carbohydrates — to the microbes in exchange for nutrients. So the microbes stop bringing nitrogen and micronutrients to the plants.
“Plants have relied on their microbiome for millions of years to get the proper mix and amount of nutrients at the right time, the right growth cycle,” Anne says. That time may be the flowering season, the fruiting season, or when pests and pathogens are abundant and plant immunity could use the microbes’ aid.
Symbiosis between microbes and plants spurs phytochemical production, and phytochemicals are linked to the plant immune system and plants’ ability to withstand drought and cold or warm temperatures.
“But when you knock the microbes off the job,” Anne says, “then the plants are like, ‘Phytochemicals, schmito-chemicals. What do I need those for? I got all this free nitrogen, and I’m gonna grow with all that nitrogen.’ Then as soon as plants start de-emphasizing phytochemical production, oh, well then plant immunity starts to suffer.”
When plants begin to be overcome by pests and pathogens, farmers often respond by applying chemicals.
“It’s probably no accident that global sales of pesticides increased after global sales of nitrogen fertilizers,” David says. “It just took us decades to figure out why.”
He adds that broad-spectrum pesticides will kill not just the pests, but also the insects that eat the pests.
“If you take an agricultural field and you spray it and wipe out the biology on it to get rid of the pests, it’s not the predators that come back first, it’s the pests,” he says. “Because they will bounce back in the absence of the predators. And so you basically create these cycles of dependency where the overuse of nitrogen fertilizer creates the demand for more nitrogen fertilizer, and more pesticide, which in turn creates more demand for more pesticide. It’s a great way to sell agrochemicals. It’s not necessarily a great way to grow healthy crops.”
David says raising organic matter in soil from 1% or 2% to about 4% would eliminate the demand for 70-80% of chemical nitrogen fertilizer.
Reestablishing microbial symbiosis in soil will restore fertility, he says, explaining that means minimizing the chemical and physical disturbance of the soil, as in no-till or low-till farming. The ground should stay covered with a cover crop between growing seasons, so there are always roots in the ground putting exudates into the soil and protecting the soil from erosion. Crop rotation will reduce pest pressure from the things that specialize in eating the crop you are growing, he says.
An after shot of Anne and David’s garden. Lots of biomass and beauty created a place of solace, respite, and food for both mind and body alike.
Photo Credit: Anne Biklé and David Montgomery
The Power of Regenerative Agriculture and Gardening
The principles of regenerative farming are powerful and can restore fertility remarkably fast, David says. “And if we did that at large scale, you could literally alter humans’ ecological footprint. We also saw how you can change the nature of your yard in a way that makes for a much more enjoyable garden. I got the benefit for years of all Anne’s work in the garden in terms of making a really beautiful, nice place out of a place that had formerly been pretty much useful only for throwing a tennis ball to get her dog to chase it.”
Fortunately, more and more gardeners and farmers are becoming attuned to the benefits of regenerative practices.
“When I wrote the ‘Dirt’ book back in 2007, there was almost no discussion of soil health in the world of agronomy, nationally or internationally,” David says. “And now you go to farming conferences and everybody’s talking about soil health, and they’re talking about regenerative agriculture, even though they don’t all agree on what it means.”
He notes that today, about a third of American farmland is farmed with no-till practices, and even more if considering conservation tillage and low till. “When we were born, there was about 1% no-till in the U.S., so there’s been a growing movement for adoption of these practices. And it’s mostly been driven by farmers and consumers.”
He says the impetus has come from the bottom up as farmers realize regenerative agriculture can actually save them a lot of money. “Because what are the biggest expenses on a North American farm right now? Diesel, pesticide, and fertilizer. And those are the three things these regenerative practices allow you to really slash your expenses on.”
Rancher, regenerative agriculture advocate, and “Kiss the Ground” documentary star Gabe Brown was a guest on this podcast in 2023, and David and Anne have visited his farm themselves. He’s a great example of someone who is putting these ideas into practice and showing the results compared to his neighbors’ farms.
“It’s amazing how fast those differences can manifest in like a decade or so,” David says. “And as a geologist, I think that’s really fast. And Gabe’s farm is one of the farms that we visited that convinced us that the effects of these practices are real. He’s incredibly transformed the soil on his farm and his ranch. There’s farmers all over the world who’ve already done this, and there’s gardeners all over the world who’ve already done this and taken degraded land like Anne did, and returned it to just astounding fertility and done it actually far faster than nature could.”
It takes nature literally centuries to rebuild an inch of soil, David says, while Gabe and other farmers including at the student farm at the University of Washington, have built a foot of topsoil in less than 20 years.
Anne says if we give nature just half a chance at organic matter cycling, allowing plants to communicate with their microbiome and have a normal plant immune system, things start to fall into place. “You reach that tipping point, and it just builds on itself,” she says.
There’s an awful lot of capability within the soil to heal itself so long as we support healing and nutrient cycling processes, she says.
Agricultural Policy Is Health Policy
“Agricultural policy is actually health policy,” David says. “Healing our land and healing ourselves, they’re related. We can address both at the same time by reforming how we farm.”
“If it’s good for the land, it’s good for us,” Anne adds. “We want that soil covered. We want living plants year round. We want diversity, we want minimal chemicals. … We all know the enjoyment and the peace and the solace and the beauty that can happen on a farm or in a garden. And you just feel that. And when you feel that, you know it’s right, and when it’s right, it’s good. It’s good for us. It’s good for the land.
Anne’s makes mulch mixed using organic matter she has collected or that the garden itself generated.
Photo Credit: Anne Biklé and David Montgomery
I hope you enjoyed my conversations with David Montgomery and Anne Biklé about what your food eats and why it matters. If you haven’t listened yet, you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
Are you conscious about what your food eats? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
Episode 052: Why Organic Matters – with Maria Rodale
Episode 100: Understanding Cover Crops: The Basics and Beyond, with Jack Algiere
Episode 116: Understanding the Soil Food Web, with Dr. Elaine Ingham
Episode 153: The Science Behind Great Soil
Episode 194: Easy No-Dig Gardening, with Charlie Nardozzi
Episode 201: Understanding Regenerative Agriculture and Permaculture, with Dr. Jake Mowrer
Episode 264: Kiss the Ground: Thinking Regeneratively, with Finian Makepeace
Episode 282: The Vital Role of Soil Bacteria in the Garden, with Jeff Lowenfels
Episode 287: No-Till Gardening and The Living Soil Handbook, with Jesse Frost
Episode 335: Better Soil Health and Crop Yields Through Regenerative Agriculture, with Gabe Brown
Episode 364: Easy Ways to Help Heal Earth in Suburban and Urban Landscapes
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joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
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joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
Geomorphological Research Group
“What Your Food Ate: How to Heal Our Land and Reclaim Our Health” by David R. Montgomery and Anne Biklé
“The Hidden Half of Nature: The Microbial Roots of Life and Health” by David R. Montgomery and Anne Biklé
“Growing a Revolution: Bringing Our Soil Back to Life” by David R. Montgomery
“Environmental Science and Sustainability” by Daniel J. Sherman and David R. Montgomery
“Dirt: The Erosion of Civilizations” by David R. Montgomery
“How much do soil health practices increase soil carbon?” by Will Fulwider, Diane Mayerfeld and Kevin Shelley of University of Wisconsin-Madison
Territorial Seed Company – Our podcast episode sponsor and Brand Partner of joegardener.com
Soil3 – Our podcast episode sponsor and Brand Partner of joegardener.com
Proven Winners ColorChoice – Our podcast episode sponsor and Brand Partner of joegardener.com
Milorganite® – Our podcast episode sponsor and Brand Partner of joegardener.com
Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast was based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Corona Tools, Milorganite, Soil3, Territorial Seed Company, Earth’s Ally, Proven Winners ColorChoice, Farmer’s Defense, Heirloom Roses and Dramm. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.
