Biodynamics, Explained: Preparation 500

What cow horns, healthy soil and the setting sun have in common.

One of the fundamental ideas behind biodynamics is that healthy vines begin underground.

Preparation 500, also known as Horn Manure, is one of the ways we work toward that goal.

Each fall, fresh cow manure is packed into cow horns and buried in the vineyard soil. There it remains through the winter, surrounded by cool, moist earth. By spring, the manure has changed into a dark, rich, humus-like material that will eventually make its way back to the vineyard.

Why the Horn?

The cow has a special place in biodynamic agriculture because of its relationship to fertility and the farm ecosystem.

The horn also creates a naturally protective container. Its keratin structure surrounds the manure while it rests underground, creating an enclosed environment for its winter transformation. Biodynamic philosophy goes further, viewing the horn as a vessel that helps concentrate and preserve the forces within the preparation.

You could think of it as a small, natural fermentation chamber buried within the farm itself.

A Little Goes a Long Way

Preparation 500 isn’t applied like manure or conventional fertilizer. Only a small quantity is needed.

Before it goes into the vineyard, we combine it with water using our vortex flow form. The water moves rhythmically through the form, repeatedly creating a vortex, breaking it and reversing the movement.

This process, called dynamization, distributes and oxygenates the preparation in the water. Within biodynamic practice, that movement is also considered an important part of activating the preparation before application.

From there, 500 is sprayed in large droplets across the vineyard floor.

Following the Rhythm of the Day

We apply Preparation 500 toward dusk.

Biodynamics looks at the farm through rhythms: seasons change, the moon cycles, tides rise and fall, and every day moves from light into darkness.

In biodynamic thinking, daylight encourages activity upward and outward toward the leaves, fruit and sun. Evening represents the opposite movement—downward, inward and toward the earth.

Because Preparation 500 is intended to support roots, humus and soil life, dusk is its natural counterpart.

The timing also makes good farming sense. Evening brings cooler temperatures and gentler light, reducing evaporation and exposure to intense heat and UV. Humidity increases, dew can begin to settle and winds often diminish—all helpful when you’re trying to deliver large droplets to the soil rather than the air.

It’s Really About the Roots

Preparation 500 isn’t about adding a large dose of nutrients. Its role in biodynamic farming is to encourage the living environment surrounding the roots—supporting soil biological activity, humus formation and root development.

And that’s ultimately the point.

A vineyard is much more than what we see above ground. The health of the fruit begins with the vine, the vine depends on its roots, and those roots depend on the enormous living system beneath our feet.

Preparation 500 is one way we nurture that relationship.

Because before we can grow healthy grapes, we have to grow healthy soil.

Next in Biodynamics, Explained: The Flow Form.