Yarrow tea is a plant-based spray used in organics and Biodynamics. Yarrow tea is derived from yarrow flowers which are picked as for the Yarrow compost preparation 502. The tea’s main role in Biodynamic wine-growing is to activate potassium or ‘light’ processes in the vines, re-vitalizing them in the same way humans feeling run down drink yarrow tea in the morning as a pick-me-up (Maria Thun (2003, p.175). Yarrow tea strengthens plants in such a way that sulphur spray treatments against powdery mildew (oidium) for example are more effective.
Yarrow tea’s other role sprayed around véraison is to help cane ripening (for both the current and following crop). Adding some stinging nettles to macerate with the yarrow flowers produces a tea capable of regulating both fungal diseases and insects (Pierre Masson: 1998, p.27). Some growers claim yarrow tea can make the subsequent wine less susceptible to oxidation (Pierre Masson: 2014, p.127).
On other crops: Yarrow, dandelion and stinging nettle teas are recommended for cereal crops, allowing a reduction in the number of sulphur treatments made on vines or fruit trees, yarrow tea is very efficient on cereals during their early growth, helping yields, keeping plants free of disease and aiding reproduction (fertility) (Pierre Masson, 1998, p.27).
Spray rates: On vineyards yarrow tea can be applied as a dynamised spray. For one hectare of crops dilute 10 grammes of yarrow flowers in 3.5 litres of [boiling] water, then dilute this concentrate in 35 litres of water (Pierre Masson: 1998, p.27). Maria Thun (2003, p.175) suggests spraying yarrow tea on vines leaves early the morning, if possible when the Moon is in front of Gemini, Libra or Aquarius (flower days).
Other uses of yarrow tea: Native Americans used Yarrow as a tonic for run-down conditions and indigestion. Other uses: stimulates digestion, expectorant, carminative (dispels gas), hemostatic (stops bleeding), astringent, antibiotic, anti-inflammatory, antispasmodic, analgesic, stimulant, and emmenagogue, general tonic for the cardio-vascular system, lowers blood pressure, slows heartbeat.
See also: Yarrow and stinging nettle tea. | Yarrow cold extract.
Bibliography
Monty Waldin., Biodynamic Gardening (Dorling Kindersley, 2015).
Monty Waldin., Biodynamic Wine (Infinite Ideas, 2016).
Pierre Masson., Guide pratique de la Bio-Dynamie à l’usage des agriculteurs (France, 1998).
Pierre Masson., A Biodynamic Manual (second edition, 2014, Floris Books, Edinburgh), revised and edited by Pierre and Vincent Masson. Translated by Monique Blais, p.127.