BD 500: Horn Manure – Nourishing the Soil with Cosmic Cow Wisdom
What Is BD 500?
BD 500 is a biodynamic soil preparation made by maturing cow manure in buried horns through winter, then stirring a small amount in water for a soil spray. Growers use it to enliven soil and encourage strong root development as part of a biodynamic soil-care program.
JPI's BD 500 is a concentrated horn-manure preparation used to encourage living-soil activity and root development. After winter maturation, stir the material for one full hour and spray promptly onto moist soil late in the day, often shortly before sowing or transplanting. Follow the current directions.
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
Preparation, purpose, and field evidence
Horn manure is a soil-directed preparation that complements compost, cover crops, and attentive farm management. Biodynamic teaching connects its use with earthly and cosmic rhythms, giving growers a larger picture of soil vitality and plant development.
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
Laboratory analyses have characterized humified organic matter in horn-manure preparations. A 2019 report of two field experiments found 12–39% greater root dry matter and 10–37% greater root length than organic treatments across wheat and maize comparisons, depending on crop, year, and preparation use. The field programs included horn manure alongside horn silica and compost preparations. In the Washington experiment, the researchers sourced their biodynamic preparations from Josephine Porter.
The Spiritual Science of Horn Manure
In Rudolf Steiner's Agriculture Course, the cow horn and manure are discussed through cosmic and astral imagery. This spiritual account gives growers a way to understand the preparation's place in biodynamic soil care.
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 placed horn manure within a larger vision of earth, planetary rhythms, and agricultural renewal. Growers can connect that tradition with their own observations of soil structure, root vigor, and crop development over successive seasons.
📚 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.
Frequently asked questions
BD 500 is a soil preparation made by filling cow horns with cow manure, burying them through winter, then stirring a small amount of the matured material in water for a soil spray. Biodynamic growers use it to nurture living soil and support root development. See the current BD 500 instructions.
Horn Manure is a soil-directed part of biodynamic preparation programs. In two wheat and maize field experiments, programs using horn manure with horn silica and compost preparations measured 12–39% greater root dry matter and 10–37% greater root length than organic treatments, varying by crop, year, and preparation use. The Washington researchers sourced their biodynamic preparations from Josephine Porter. These experiments document stronger root development within a BD 500-inclusive program.
For JPI’s current one-acre direction, stir one ¼-cup unit in 3 gallons of lukewarm rainwater or chemical-free water for a full hour, reversing the stirring direction repeatedly. Spray promptly onto moist soil in the latter part of the day, often shortly before sowing or transplanting; avoid drought, strong wind, and imminent rain. See the full instructions and smaller-area proportions.
Yes. BD 500 can be used in a home garden or at farm scale by adjusting the one-acre dose proportionately. Use clean equipment and water, spray the soil rather than foliage, and choose moist-soil and calm-weather conditions as described in the JPI instructions. It fits naturally alongside compost, cover crops, and other biodynamic soil-care practices.
Use this preparation: Shop BD 500 Horn Manure · BD 500 application instructions
