Biodynamic autumn: what happens inside the cow horn

Autumn Journey 2026 · Part 4 of 5

While the garden settles down, biodynamic farms begin one of the most unusual jobs of the year: cow horns are filled with fresh cow manure and laid in the ground. There they stay all winter. What is dug up again in spring no longer smells of manure, but of forest soil.

Sounds strange? It is a little. And that is exactly why it's worth a closer look – at what is done, and at what is known about it.

Horn manure (preparation 500): a winter in the horn

For horn manure, cow horns are filled with cow dung. According to Demeter, the filling then spends "half a year" in the ground – through the cold season. Afterwards the "dark, earthy mass" is stirred into water ("dynamised") and sprayed on the land. Demeter farms apply horn manure at least once a year.

Practical guides give very concrete details. Biodynamie Services, for example, recommends:

• stirring vigorously for exactly one hour,
• spraying in the evening, on a day that is not too windy or too hot,
• on warm, moist soil, generally in spring and autumn,
• about 100 g per hectare in at least 30 to 35 litres of water; for areas under 1,000 m², 10 to 20 g in 5 to 10 litres.

For your garden this means: a bucket of water and a small amount of preparation are enough for a bed. You can get preparations from biodynamic farms or preparation groups.

Horn silica (501): the counterpart for light

The second spray preparation is horn silica: finely ground quartz, also in a cow horn, also half a year in the ground. Unlike horn manure, it is sprayed onto the plants, not the soil (Demeter).

Six medicinal plants for the compost (502–507)

Autumn is compost time too. Biodynamic farms add six preparations in tiny amounts to manure or plant compost:

No.	Plant
502	Yarrow
503	Chamomile
504	Stinging nettle
505	Oak bark
506	Dandelion
507	Valerian

According to Lebendige Erde, the preparations are packed into moist balls of clay, pushed into the compost heap and covered again; the valerian is poured over the top. This is how the year's waste becomes next year's fertility.

And what does science say?

Honestly: not much that is final yet. Demeter itself writes that the way the preparations work is "only beginning to be researched" and that "many questions are still open" – while several studies indicate positive effects on certain traits (Demeter). The effects described belong to the biodynamic tradition; they are not established mechanisms.

The exciting part: you can observe it yourself. Preparation sprayed, preparation not sprayed – same crop, same care, recorded in your journal over a few years.

Planning biodynamically with PermaNatura

When is a root day, when a fruit day? When you create a task in the calendar, PermaNatura shows the biodynamic day of the chosen date – and suggests the next fitting day for sowing and harvest. With the task templates "Spray horn manure (500)" and "Spray horn silica (501)", the job is planned in one tap. Learn more in the preparations section.

The Autumn Journey 2026

1. Stop for one minute: how to read your autumn garden
2. Sweet chestnut or horse chestnut? The check before you gather
3. One tree, many cycles: what the sweet chestnut teaches about permaculture
4. Biodynamic autumn: what happens inside the cow horn (you are here)
5. The farm cycle in autumn: pasture, animals, manure

Frequently asked questions

Can I use preparations in a home garden?

Yes. The amounts for small areas are very small; sources are biodynamic farms and regional preparation groups.

Do I have to believe in the effect?

No. You can treat the practice as an experiment and document your own observations.

As of 20 October 2026. Details on making and using the preparations follow Demeter, Lebendige Erde and Biodynamie Services; amounts and timing are practical recommendations, not a guarantee of any effect.