Last week we took delivery of our very own compost tea brewer, courtesy of the team at Laverstoke Park.
Compost tea is a water based extract of compost that is "brewed" aerobically to extract organisms (bacteria, fungi, protozoa and nematodes). This is done by filling the tank with de-chlorinated water and submerging some woody compost into it (contained in a fine mash bag). Air is then pumped into the tank from the bottom (a bit like a bubble bath) for 24-36 hours.
Feed stimulants can be added to the brew to promote growth of specific organisims. In our case we're using fish and seaweed extracts to encourage the growth of fungi. When the tea is sprayed on the vines these organisms dominate the surfaces of the leaves which hopefully prevents disease-causing organisms from establishing, particularly mildews. Compost tea also provides plant food which aids healthy plant growth, strengthens the plant's defence systems and, with the addition of beneficial organisms to the soil, will help the recycling of organic matter, improving soil structure.
The tank has a capacity of 1000 litres which should be enough to spray the vineyard when we have planted the full 13 acres and the canopy is fully developed. We are planning to make a brew about every two weeks.
During the growing season Laverstoke will be analysing our compost tea every month to ensure that it has the right level and type of organisms for our soil.
We have no intention of competing with the local excellent hop brewery near Shere, or indeed Philip's magnificent brew of "English Breakfast", but hopefully our compost tea will be just the right brew for the vines.