A distinguishing feature of bio-dynamic agriculture is the use of eight preparations made from herbs, mineral substances and animal manures that are utilized in field sprays and compost inoculants. They are applied in minute doses, much like homeopathic remedies are for humans. As required by Demeter International, preparation use is necessary for biodynamic certification.
These biodynamic preparations are numbered 500-508 :
A- Preparation 500 is made from fermented cow manure and is usedas a soil spray to stimulate root growth, humus formation, and microorganism development.
B- Preparation 501 is made from powdered quartz and applied as a foliar spray to   encourage photosynthesis.      
C- Preparations 502-507 are herb based compost inoculants.

D- Preparation 508 is created from dried Equisetum (Horse Tail) and is utilised for disease control.

As much as possible, the biodynamic preparations should be made on the farm or within the farm’s community, with ingredients from the farm or region. At the moment, EBDA makes all of the preparations for its members.

Note: This is an excerpt of "Biodynamic Farm Standard (2010). Demeter Association Inc."