Comfrey Liquid Manure is made from Comfrey (Symphytum officinale). It is a popular liquid manure used in organic farming and home gardening. Like stinging nettle, comfrey is a rich source of nutrients and trace elements: iron, phosphorus, calcium, potassium, sodium, manganese, chromium and selenium. Comfrey is especially good for fruiting and seed filling crops because it stimulates potassium processes, aiding photosynthesis and reinforcing plant self-defence mechanisms, eg. against downy mildew in viticulture (Pierre Masson: 2014, p.137). It de-stresses vines after hail, and like seaweed can aid boron deficiency at flowering. The shoots and leaves are picked at the beginning of flowering. Comfrey can also be used as a tea. See plant-based sprays.
Bibliography
Monty Waldin., Biodynamic Gardening (Dorling Kindersley, 2015).
Monty Waldin., Biodynamic Wine (Infinite Ideas, 2016).
Pierre Masson,. A Biodynamic Manual, (2nd edition 2014, Floris), p.137.