Late summer in the author’s garden. (Barbara Damrosch/Barbara Damrosch)

One day in the spring of 2001, I sat in a coffee shop near the Washington Post offices, talking with garden editor Adrian Higgins. A book of mine I'd just updated, on ornamental gardens, sat between us on the table. The burning question, for both of us, was "How can we get people to grow food?"

Two years later, when I launched my column "A Cook's Garden" for The Post, people were still putting lawns and lilies ahead of lettuce and kale. Now, 14 years later, that has changed. Americans are caught up in a sod-busting, tomato-canning, chef-worshiping food revolution.

For my part, it's time for me to end this series and spend more time in the garden outside my kitchen window. But I leave it on a happy note. Although the recession of 2008 certainly fueled the grow-your-own boom, the boom has not slowed. A National Gardening Association survey found that food gardening increased 25 percent between 2008 and 2015. Recently, a publisher complained to me: "I can't sell a rose book. I can sell books on chickens. Why?"

There are many answers. People have concerns about the industrial food system, its factory-like farms, its harm to the environment and its degradation of the soil. The food you grow at home tastes better and the act of growing it rewards you, both physically and mentally. It's given a big boost to home cooking as well.

But there's more. I say we are at the dawn of a new biotic age. Just as we've been negotiating our way between two parallel but very different forms of agriculture — one large-scale and chemically based, the other localized and biologically based — we've been caught between two modes of thought. This paradox is not just about growing food but about how we interact with nature in general. Both approaches can't exist at once. As in 1492, the Earth is either round or it's flat.

I've always thought of horticulture as the humble science, maybe because I practice it on my muddy knees rather than from the cab of a huge computerized combine. But a science it is, and all the more challenging because it shows us how much we don't know and how little we are in charge.

And who is in charge? The microbes. Sure, we've known about bacteria, fungi and all the other essential no-see-ums for a long time, but every day we're shown more about how numerous and complex their systems are and how they steer life on the planet.

Consider our planet's skin, the soil and the bit of it you allocate for your garden. We're told that it needs nitrogen, potassium and phosphorous in good balance and a collection of other minerals such as calcium and iron. But unless the soil is alive, it might as well be on the moon.

We also know about the rhizosphere, the area where a plant's root hairs partner with microbial teams. The roots exude carbon sugars that feed microbes, which return the favor by making soil nutrients available in forms that the plants can use. But soil scientists are just discovering how numerous and diverse these microbial communities are in a healthy, fertile soil.

A plant will select an appropriate microbial community that will not only feed it and make it grow well but also fend off harmful bacteria and fungi. The suitability of a plant's chosen range of microbes, acting in concert, has even been referred to as a "second genome."

Similar exchanges take place in the human gut, with enormous implications for our health, as well – not just for the intestines but for the whole organism. That's humbling indeed. It's like finding out that the guys in the mailroom have been running the company.

It requires an abundance and a diversity of microbial life for systems like these to flourish, and it takes forbearance on our part to allow it. It's a big mental shift to go from treating nature as individual elements to seeing it as infinite communal interactions.

Just as antibiotics, originally cultured from soil organisms, can have the side effect of upsetting our intestinal flora, so any biocide – be it weed killer, bug killer or chemical food – will compromise the life in the soil.

As a gardener of the biotic age, the best thing you can do is add organic matter to the soil in the form of homemade compost, or legumes and grasses dug in as cover crops, and let the microbes go to work. Stand back and don't get in their way.

You'll know your soil is fertile when its color is dark and its structure loose and open. Your plants will show health and vigor. Worms will appear, and when you see them, you'll know that all the tiny guys are in there, too.

Tip of the Week

Stock up on horticultural row cover fabric in advance of frost season. Fending off one night of early frost can prolong the growing season for tender plants such as peppers, beans and annual herbs. The reusable spun plastic material is also useful for extending salad green season and is available in hardware stores and garden centers and by mail order.

— Adrian Higgins