Horsetail Soil Spray – March 25th

This is our first blog about the specific biodynamic activities undertaken in the year. The aim of these blogs is to explain these processes – how, why and when we do them – so that others can follow them if they are interested. We will also link to our sources of information.

The first biodynamic treatment of the year was an Equisetum Soil Spray. This is based on advice from Vincent Masson 1, an experienced biodynamic agricultural consultant in France. Masson recommends that, “if a vine is sensitive to mildew, spray horsetail decoction [Equisetum] on the ground before bud-burst (before Easter)”. The aim of this spray is to reduce the impact of powdery mildew on the vines, working at ground level before the buds have burst.

Monty Waldin 2 describes Horsetail as being “so luminous it could almost be nature’s equivalent to a lightsaber” due to its extremely high silica content. He notes that it is the silica that “gives the horsetail its drying or ‘tightening’ effect, like silica sachets”, and it is partly this quality that helps discourage fungal growth on the plant.

In the first year following planting, our Pinot Noir vines had some powdery mildew on their leaves and so we will be working this year to minimise this as much as possible. Our other vines which are mainly Interspecific Hybrids 3 (Orion, Rondo, Regent, & Solaris) were almost unaffected – small patches on some of the Orion leaves but nothing significant.

The recommended time to do this spray is the week before Easter. 

Ingredients (for about 1 Ha vines)

  • 100-120g/Ha dried Equisetum arvense (Horsetail)
  • 5L rainwater to make the decoction
  • 35-70L rainwater for mixing to make the final spray


Add the Equisetum arvense to the pan of water and bring to a light boil. Boil for 40-60 minutes (we boiled it for 60 minutes). This makes the decoction.

Fill your dynamising vessel with 35-70L/Ha rainwater (we used about 60L for our vineyard of just under a hectare), add the decoction and dynamise for 20 minutes.


Spray on the area under the vines, between the vine rows and around the field, ideally using a copper tanked sprayer. We used a copper backpack sprayer with brass arm/nozzles – see image below. We did not spray on the vines as there was no leaf growth at the time.

Masson, P. & V. (2012) A Biodynamic Manual, Floris Books (p. 274)

 Waldin, M. (2012) Biodynamic Wine Growing: Theory & Practice, Published by Author (p. 34)

3 Interspecific Hybrids are vine varietals that have been cross-bred from different vine species to manifest certain qualities – disease resistance, shorter ripening times, taste, etc. and so are particularly useful for growing organically in the English climate.

Dynamising is the process of mixing and energising liquids, recommended by Rudolf Steiner. It involves stirring the mixture one way to create a vortex, then stirring the other way, initially creating a chaotic mix and then a vortex in the opposite direction. This is then repeated in a constant rhythm for the appropriate length of time (20-60 minutes, dependant on the preparation).