A distinguishing feature of biodynamic farming is the use of nine biodynamic preparations described by Steiner for the purpose of enhancing soil quality and stimulating plant life. They consist of mineral, plant, or animal manure extracts, usually fermented and applied in small proportions to compost, manures, the soil, or directly onto plants, after dilution and stirring procedures called dramatizations. 

In theory, they are best interpreted as homeopathic treatments applied to the soil or compost, whereby small amounts have a tremendous impact on soil enhancement, fertility and vitality.

The original biodynamic (BD) preparations are numbered 500-508. The BD 500 preparation (horn-manure) is made from cow manure (fermented in a cow horn that is buried in the soil for six months through autumn and winter) and is used as a soil spray to stimulate root growth and humus formation. The BD 501 preparation (horn-silica) is made from powdered quartz (packed inside a cow horn and buried in the soil for six months through spring and summer) and applied as a foliage spray to stimulate and regulate growth. The next six preparations, BD 502-507, are used in making compost. 

Finally, there is BD preparation 508 which is prepared from the silica-rich horsetail plant (Equisetum arvense) and used as a foliage spray to suppress fungal diseases in plants. 

The BD compost preparations are listed below:

• No. 502 Yarrow blossoms (Achillea millefolium)
• No. 503 Chamomile blossoms (Chamomilla officinalis)
• No. 504 Stinging nettle (whole plant in full bloom) (Urtica dioca)
• No. 505 Oak bark (Quercus robur)
• No. 506 Dandelion flowers (Taraxacum officinale)
• No. 507 Valerian flowers (Valeriana officinalis)

Biodynamic preparations are intended to help moderate and regulate biological processes as well as enhance and strengthen the life (etheric) forces on the farm. The preparations are used in homeopathic quantities, meaning they produce an effect in extremely diluted amounts. As an example, just 1/16th ounce�a level teaspoon�of each compost preparation is added to seven- to ten-ton piles of compost. 

More Detailed Information on BD Preparations

More specific instructions on biodynamic preparations, placement in the compost, compost making, and compost use can be found in a number of publications available through the Biodynamic Farming and Gardening Association.