501 cow horn silica biodynamic preparation

501 cow horn silica biodynamic preparation

The 501 cow horn silica biodynamic preparation is one of the two key preparations that must be used for a farm to be certified biodynamic. It is used to bring light into the vineyard and reinforces the health and vitality as well as improving the verticality (important for vines), the leaf surfaces and the fruit skins.

20180725_132409_resized_1The other key prep is the 500 or horn manure preparation.

The dose is tiny – less than a teaspoon – diluted in around 30 litres of pure unpolluted water per hectare then dynamised and then sprayed into the air.


Sean has always been wary of the 501 given the hot summers of South West France. At the start of 2016 with the cold, rainy spring, I convinced him to do a second spray of 501 on part of the vineyard, taking the cue from a biodynamic colleague in Jura who saved his crop in 2013 with 11 passes of 501. But the cold wet spring catapulted into hot summer with a peak of forty degrees within ten days of our silica spray. The 501 magnifies heat and light forces- when I walked passed our young Cabernet sauvignon the day after 40deg, parts of it were burnt, like someone had passed through with a flame thrower. I felt culpable for their pain and Sean gave me a ‘told you so’ look. Fortunately the vines survived.


The photos are of Sean doing the spray in June 2018.

If you find this illuminating please share this article. Do you pick up taste differences between biodynamic and chemically farmed wine? I would appreciate comments/ your experiences.

Read our new Biodynamic trail information series part of a visit you can do in the vines at Chateau Feely.

See our series on why organic and read more about biodynamics. Come and learn more about organic and biodynamic farming with a visit to Chateau Feely in South West France ; stay with us or do a multi day course or multi day tour . You can read about the story of our organic farm the series includes three books Grape ExpectationsSaving our Skins and Glass Half Full by Caro Feely. Join our mailing list to receive our seasonal newsletter, wine school, events, wine pairing, recipes and more info on this topic at the bottom right of this page.

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