Let’s welcome the Estival Solstice, the first day of summer, a simple astronomical event with a stunning array of effects on Earth. Now begin gradually shorter days and longer nights, barely perceptible in late June’s splashy technicolor landscape.

In a single moment, the sun’s course reverses, beginning a gradual pivot, arcing from the northern to the southern hemisphere, nudging us Northerners toward winter. We live in a clockwise universe.

Today, we bid farewell to spring—the manic kaleidoscopic swirl of seedlings, sprouts, shoots, young leaves and blooms springing up and dancing around us—and shift into prolific summer, the mature season, the prime of our planet’s plant life.

Summer Solstice begins the year’s vegetative (think vegetables) phase of spreading foliage, lengthening stems, dilating leaves reaching out for yet more solar rays, and flowers tuning their colors and sweetening their nectar—all to ensure pollination and fruit set. An annual vascular plant’s only goal is to reproduce; a seed uses a plant to produce more seeds.

If you find the Solstice intangible and remote, you can observe cosmic clockwork up close here on Earth: gaze through its sunlit crystal and behold its lush green dial—what we call a garden. And you are the spring that powers the garden clock.

A few skeptics insist it’s off-putting to describe the garden as a “machine”. My friends advise me that no one—save perhaps futurist Ray Kurzweil—wants to be a machine. It’s not aspirational; it’s off-trend. I reply to them that the garden is the only living machine that humans make.

The 17th-century philosopher René Descartes would agree with me. He wrote, “I suppose the body to be nothing but a statue or machine made of earth.” Perhaps we can extrapolate, “I think, therefore I garden.”

In 16th-century Europe, clocks were the most advanced devices, high-tech sensations, the internet of their time. They were the rage among royalty, scholars and monks. Cathedrals featured giant elaborate astronomical clocks with synchronous displays of puppet-like automata portraying the Virgin Mother, processions of monks and other motifs from scripture, the heavens and nature.

Situated behind the altar, the holy timepieces conveyed the orderly motions of God’s universe to the faithful. The Church and secular scientists agreed: the world and the heavens functioned like machines. Worth noting: the round faces of clocks and watches are a legacy of the gnomon and sundial, timekeepers for which Earth is the single moving part.

The garden is a kindred mechanism: a combination of clock and weather station. Plants are attuned to the lengths of day and night, seasonal changes, and the slightest variations in temperature and humidity. They can reflect time’s passage. Plus many taste delicious and make lasting memories. Can your Fitbit do that?

Plants are remarkably self-sufficient. They produce their own food, pump their own water, exchange messages with other plants, pollinators and predators. They orient themselves for maximum sunlight, absorbing nearly all they are exposed to. Once they’ve had their solar fill, they turn shiny to deflect the sun. When necessary, plants can migrate across oceans and continents.

Plant parts are no less ingenious. High altitude tropical epiphytes—air plants—turn their roots into crampons to grip the tree or rocky crag where they reside. Exposed to the sun, the roots turn green by day so they can photosynthesize—the leaves’ job. Role reversal continues: the leaves reach high into the air and by day inhale nutrients from ambient dust, and by night absorb water from the fog and mist—the roots’ job.

But in their new homes, domesticated plants need our help—a gardener ex machina—to change a plot of land into a garden. The first step on the garden path is building an enclosure to protect its plants from invaders large and small. Good fences make good gardens.

Like the clocks of Renaissance Europe, our gardens are cultural as well as mechanical. We present ourselves to the world through our plant choices, design ideas and decisions about nutrition and disease control. Gardens represent our identity, personality and ingenuity much like the church clocks reflect the ideals of their builders. We are what we garden.

Each plant needs its own unique calibration of cultivation and care within our garden’s extensive network of soil, light, air and water. Like the Renaissance clock, every garden is a machine with its own set up, operation and maintenance.

Does our garden plant require more or less sun? How much clay, sand or loam does our soil need; is it too acidic or alkaline? Should we sow before or after last frost? Should we fertilize now, later or never? Soon enough we develop brain and muscle memory and become our garden’s mechanic.

Thereby we experience our garden in unprecedented ways—seeing new sights, feeling new emotions. The garden turns us on, so to speak, giving us more motivation necessary for its survival. We work happily, most of all at the menial tasks. We thrive as the springs of the earthly and cosmic garden clock.

Happy summer.

A version of this article appeared in The Spokane Spokesman-Review, The Fayetteville Observer and the Asbury Park Press.