BD 508: Equisetum – The Lunar Healer of the Compost

What Is BD 508?

BD 508 is made from Equisetum arvense, a plant commonly known as horsetail. Unlike the other biodynamic preparations, BD 508 is not used in compost, but as a foliar or soil spray to help manage excessive moisture and fungal conditions.

Although it is one of the most powerful biodynamic remedies, it was once almost forgotten:

When I began distributing the preparations following Josephine Porter’s death in 1984, I was troubled by the fact that two of the preparations... seemed to be of virtually no interest to anyone ordering preparations. Those two were BD 501... and BD 508, Equisetum arvense or horsetail herb.
– Hugh J. Courtney, Applied Biodynamics, no. 68 (2010): 184.¹

This preparation is most often used to control fungal diseases, reduce mildew, and regulate excess moisture in soil or air.

How BD 508 Works

BD 508 can be prepared in several ways. The most common is a decoction, where dried horsetail is simmered, fermented, and then applied as a spray. The extended fermentation enhances its effectiveness:

Take one unit of shredded Equisetum arvense ... Bring to a boil in one gallon of water and simmer for one hour... allow to ferment ten to fourteen days ... One unit of horsetail can thereby treat up to three acres with as powerful effect as can be achieved by the fresh tea recipe on only one acre.
– [Attributed to Hugh J. Courtney], Applied Biodynamics, no. 68 (2010): 192.²

Unlike BD 500 and BD 501, BD 508 is not stirred or dynamized. It is simply applied with awareness and rhythm, often around the full moon or in particularly wet years. It acts as a corrective spray, helping plants and soil recover from conditions that lead to disease.

The Spiritual Science of BD 508

BD 508 is deeply connected to the moon. It is said to normalize lunar influences on water processes in the soil and plant. Hugh Courtney linked it directly to the sensory system of the farm organism:

It is BD 501, and especially BD 508 (by virtue of its ‘normalization’ of the moon’s earthly energies), that stimulates the sense organs of the farm individuality... Without that stimulation... the other members of the solar system cannot bring to bear their powers...
– Hugh J. Courtney, “Revealing the Hidden Forces of Equisetum arvense,” Applied Biodynamics, no. 68 (2010): 204.³

BD 508 does not force the farm into balance; rather, it restores receptivity. It clears the way for the subtle influences of the sun, planets, and cosmos to enter into relationship with the earth.

📚 Footnotes

1. Hugh J. Courtney, “Revealing the Hidden Forces of Equisetum arvense,” Applied Biodynamics, no. 68 (2010): 184.
   
2. Ibid., 192. 
   
3. Ibid., 204.
   
   

 

Frequently asked questions

What is BD 508 horsetail, and is it a compost preparation?

BD 508 is made from Equisetum arvense (horsetail) and prepared as a fresh-tea foliar spray or a fermented-tea soil spray. BD 502–507 are placed separately in compost, giving each preparation a clear role in biodynamic practice.

Why do biodynamic growers use BD 508?

JPI’s biodynamic guidance uses horsetail in moisture-prone conditions as part of preventive fungal management. It complements airflow, moisture management, and close plant observation in an integrated approach to healthy growing conditions.

How do I prepare and apply BD 508?

JPI provides fresh-tea and fermented-tea methods with distinct preparation and application directions. Follow the current BD 508 instructions for the method, quantities, and coverage so the foliar and soil uses each retain their intended role.

How does BD 508 relate to lunar rhythms in biodynamic practice?

Hugh Courtney described BD 508 in relation to the moon and water processes within a biodynamic framework. Growers can explore this traditional relationship through dated applications and observation while also tracking local weather, plant condition, and the current JPI method.

What habitat does common horsetail favor?

Common horsetail often grows in open places with moist subsoil. It can tolerate strong sun and a drier-looking surface when its underground rhizomes reach a steady water supply below.

For BD 508, are green horsetail shoots used or the brown spring shoots?

BD 508 uses the green above-ground shoots of common horsetail (Equisetum arvense). The brown spring shoots bear spores and represent a different growth stage of the plant.

How does common horsetail reproduce?

Common horsetail (Equisetum arvense) reproduces through spores and spreads through underground rhizomes. Its brown fertile shoots bear spores, while the green branching shoots provide the plant material used for BD 508.

 

Use this preparation: Shop BD 508 Horsetail · BD 508 application instructions