To reduce the risk of mildew on the vines we spray with a special anti-fungal mist regularly, approximately every couple of weeks dependant on the weather. This first spray was done just after bud burst. The spray is based on recommendations by Helmut Wolf 1 of Zwoelberich Vineyard (Germany), Monty Waldin 2 and Vincent Masson 3 and includes Horsetail (Equisetum arvense), organic whey, organic essential oils, and Yarrow (Achillea millefolium).
The reasons behind the ingredients are varied – when you spray whey onto the vine leaves, they alter the surface pH levels, making them inhospitable to the powdery mildew spores; the terpenes and esters in the essential oils have anti-fungal properties which kill the spores; the Horsetail acts to ‘dry out’ the leaves making the environment less hospitable to mildew spores (see previous blog); and the Yarrow reduces the need for sulphur sprays, with its high sulphur content.
We collected the Horsetail and Yarrow last year and dried them to use this year, before the fresh plants are available to use. The organic essential oils were bought from a local producer in Bristol, and we made the whey ourselves from Yeo Valley milk & yoghurt.
Ingredients (for about 1 Ha vines)
- 100-120g/Ha organic dried Equisetum arvense (Horsetail)
- 10g/Ha organic dried Achillea millefolium (Yarrow)
- 8L rain water to make the decoction & tea
- 5ml organic thyme essential oil
- 5ml organic eucalyptus essential oil
- 1L organic whey
- 35-70L rain water for dynamising to make the final spray
You can make whey yourself from natural yoghurt, or you can contact a cheesemaker for their leftover whey. We used a spoonful of Yeo Valley organic natural yoghurt, and some of their milk, to make 2L of our own yoghurt 4, and then strained it overnight to separate the whey 5. (Btw. when you strain the yoghurt you end of with about 1L whey and 1L greek yoghurt which tastes fantastic).
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.
Once it has boiled switch off the heat and add the Achillea millefolium. Allow this to steep for 20 minutes, then strain. This creates a combined decoction/tea.
Add the essential oils to the whey and mix well to emulsify. We added the 1L whey and oils to a 2L bottle, put the lid on and shook for a few minutes.
Fill the dynamising vessel with 35-70L/Ha rainwater (we used about 60L for our vineyard of just under a hectare), add the decoction/tea and whey/oil mix and dynamise for 20 minutes (if you’re from the north it creates a head like a pint of Boddingtons bitter.)
Spray on the vines, trunk and leaves with a fine mist setting on the sprayer.
1 Helmut Wolf is the vineyard manager and winemaker for Zwölberich Vineyard in Langenlonsheim, Germany. Zwölberich has been biodynamic for over 20 years and produces wonderful biodynamic wines, with great depth of flavor, terroir specificity and individuality. They are also near a fantastic spa in Bad Kreuznach – a visit to both (as we discovered) may well be the perfect holiday.
2 Waldin, M. (2012) Biodynamic Wine Growing: Theory & Practice, Published by Author (p. 35)
3 Masson, P. & V. (2012) A Biodynamic Manual, Floris Books (p. 168 & 276)