BD 500: Horn Manure – Nourishing the Soil with Cosmic Cow Wisdom
What Is BD 500?
Imagine if your garden could eat a magic smoothie that makes the soil healthy, helps plants grow stronger, and even brings in some sunlight from the stars. That’s kind of what BD 500 is.
BD 500 is a special plant food made by packing fresh cow manure into a cow horn, burying it in the ground over the winter, and then digging it up in spring. When it’s done, the manure isn’t stinky anymore — it smells like rich, fresh forest soil. Just a tiny bit of this is stirred in water and sprayed on the farm or garden. It helps everything grow better — not because it’s fertilizer, but because it carries a kind of Earth magic.
And you don’t have to be an expert to try it. As one biodynamic farmer once said:
Try it, you’ll like it!
– Hugh J. Courtney, Applied Biodynamics, no. 9 (1994), 49.¹
How BD 500 Works
BD 500, or horn manure, is not about adding nutrients like nitrogen in the conventional sense. It's about stimulating microbial life and enhancing the soil’s rhythmic relationship to the cosmos.
To make it, fresh cow manure from a healthy lactating cow is packed into a cow horn and buried in the fall, typically near the Michaelmas season. Over the winter, the manure undergoes microbial fermentation and transformation—a humification process. When unearthed in the spring, it should smell earthy, sweet, and alive—a sensory test practitioners know well:
Often, the first step is to smell the manure in the horn, hoping that my nostrils will detect an earthy smell, rather than any odor resembling the raw cow manure that was packed into the horns the previous Fall.
– Hugh J. Courtney, Applied Biodynamics, no. 9 (1994), 51.²
Chemically, BD 500 is rich in humic substances, beneficial microbes, and mineral complexes that stimulate soil structure, root growth, and mycorrhizal associations. Stirring it rhythmically in water (called dynamization) activates these forces and helps broadcast their effects across the field.
The Spiritual Science of Horn Manure
In Rudolf Steiner’s Agriculture Course, BD 500 is not just a biological input—it’s a vessel for cosmic and astral forces. The cow’s horn, he says, is an organ that rays back life-giving impulses from the digestive processes into the etheric field of the animal—and thus, when used ritually in the earth, it continues to serve this etheric-astral function.
Hugh Courtney, in early Applied Biodynamics, emphasized that the form and origin of the horn are not symbolic but functional in spiritual terms:
We preserve in the horn the forces it was accustomed to exert within the cow itself, namely the property of raying back whatever is life-giving and astral.
– Rudolf Steiner, quoted in Hugh J. Courtney, Applied Biodynamics, no. 5 (1993), 46.³
Steiner described BD 500 as a way to reconnect the Earth with the higher spheres of planetary and zodiacal influence—rooting terrestrial life in the rhythm of the cosmos.
📚 Footnotes
- Hugh J. Courtney, “Further Thoughts on Making BD 500,” Applied Biodynamics, no. 9 (1994): 49.
- Ibid., 51.
- Hugh J. Courtney, “The Foundational Horn Manure Preparation,” Applied Biodynamics, no. 5 (1993): 46.