Soil

What soil does for the vine

Soil does four things. It anchors the vine physically. It provides water through rainfall and irrigation. It supplies nutrients, mainly nitrogen, phosphorus, potassium and a long list of micronutrients. And it houses a complex microbial ecosystem that interacts with the vine's roots, helping it to access nutrients and resist disease.

The soil's physical structure matters more than its mineral content. A free-draining soil, like the chalk of the South Downs, forces the vine to send its roots deep in search of water. The vine's stress is part of what gives the wine its character. A water-retentive soil, like a heavy clay, gives an easier ride and a different style of wine.

The chemical side

Soil pH, the acidity or alkalinity of the soil, has a big effect on nutrient availability. Most UK vineyard soils sit between pH 5.5 and 8.0. Acidic soils, below pH 5.5, can lock up nutrients and require lime application. Alkaline soils, above pH 8.0, can cause iron deficiency and other issues. The chalk soils of the South East are naturally alkaline, which suits Chardonnay and Pinot Noir particularly well.

Major UK soil types

Chalk is the most celebrated UK vineyard soil, found in the South Downs, the North Downs, the Chilterns and parts of the South West. It is the same chalk that runs under the Channel into the Côte des Blancs, which is one reason English sparkling wines can compete with Champagne. Chalk gives free drainage, low fertility, high pH and a mineral character to the wine.

Greensand, found in parts of the Weald and East Anglia, is a sandstone soil with a greenish tint from glauconite. It is free-draining and slightly acidic, suited to aromatic whites such as Bacchus. Clay, found in the London Basin and parts of the South East, is more water-retentive, suited to varieties that prefer a cooler root zone. Loam, slate, granite and volcanic soils are also found in the UK, each with their own character.

Soil management

UK growers manage soil through a combination of cover cropping, composting, mulching and tillage. Cover crops, usually a mix of grasses, legumes and herbs, are planted between the rows to prevent erosion, add organic matter and provide habitat for beneficial insects. The cover is mowed or rolled several times a year, and the cuttings are left to break down on the surface.

Compost, made from grape marc, manure and green waste, is applied periodically to add organic matter and feed the soil microbes. Mulching with straw or wood chip helps retain moisture and suppress weeds. Tillage, increasingly done with inter-row mowers and undervine tools, replaces herbicides. The aim is a healthy, living soil that supports a healthy vine.

Why soil matters in the UK

Soil is one of the great arguments for English wine. The South East chalk, in particular, is a genuine world-class vineyard soil, capable of producing wines of real finesse and depth. The diversity of UK soils, from chalk to greensand to clay to slate, gives winemakers a real palette to work with. As the industry matures and producers get to know their specific sites, the soil conversation is becoming more important.