Pruning wash, Pruning paste 

The late François Bouchet (2003, p.163) described a pruning wash (see plant-based sprays) similar to one used by fruit growers. This is applied in autumn after leaf fall, either on the vine wood or on the soil (or both), then again at the end of winter after pruning. Bacteria in the pruning wash the vine wood clean of pathogens. For one hectare of vines 240g of Maria Thun’s barrel compost 502-507 is mixed with between 1 and 2 litres of whey from cow, goat or ewe’s milk. In addition bentonite or montmorillionite clay is pre-mixed into a lumpy paste by diluting it in water and this is then added to the manure/whey mixture at a dose of 1%. The clay simply helps stop spray nozzles from blocking. Before using, the barrel compost 502-507, whey and clay mixture are diluted together in water and dynamised for 20 minutes. The dynamised spray should be used within 48 hours of preparation. Bouchet (2003, p.120-121) says one should always leave a three week gap between applying pruning wash and spraying horn manure 500, so as not to create an opposition between the ‘building up’ forces carried by the Horn manure 500 and the decomposition forces carried by the six compost preparations 502-507 in Maria Thun’s barrel compost.

Pierre Masson’s pruning wash is made by soaking 15 litres of fresh cow manure in a porous sack in 100 litres of rainwater to make a manure tea (Masson: 1998, p.33). Then, in another recipient, 15kg of dry clay, preferably kaolin or potting clay (which Masson says is less easily washed off by rain than montmorillionite or green clay) is mixed in 100 litres of rainwater to make what should look like a light clay soup. This will help the paste to stick. The clay soup and manure tea are mixed together. Masson suggests adding 20 litres of whey too if it is available. The mixture can be topped up with 80 litres of water, or water mixed with either Horn manure 500, Prepared horn manure 500 + 502-507, Maria Thun’s barrel compost spray 502-507 or Equisetum arvense or common horsetail 508 (decoction).

New Zealand wine grower James Millton of The Millton Vineyard suggests that to make up to 20 litres of paste requires 400 grams of Cow Pat Pit stirred 20 minutes in warm (38 °C) water, 2kg of bentonite powder, 400g of diatomaceous earth and 5 litres of whey.

Bibliography

Monty Waldin., Biodynamic Gardening (Dorling Kindersley, 2015).

Monty Waldin., Biodynamic Wine (Infinite Ideas, 2016).