It is difficult to rationalise soils, as;

• Quality is more important than quantity
• Quality in wine involves individuality or typicity & so there is no absolute

Growers in traditional wine-producing countries maintain that the soil on which the vine is grown is vital to the character of the wine produced, but very little hard evidence has been brought to light to support this view. In fact, apart from possibly the pH of the soil, no other chemical constituent has been proved to confer any particular quality to particular wines.
Vines grow successfully on a wide range of soil types, as long as the rootstock is appropriate and the vine's minimal nutritional requirements are met. Fertile soils, however, are not very appropriate to vine growth as they encourage vigorous vegetation that can cause problems.

Much more important than its chemical composition is the soil's structure and texture. These affect its water retention and drainage properties. Vines do not grow well on poorly drained soils as these are cooler and take longer to heat up in spring and restrict root growth leading to a reduced resistance to drought and an increased risk of mineral deficiency. Poor drainage will also reduce the bearing capacity of a soil, causing problems when passing machinery through.

To assess poor drainage, look for:

• Water lying in pools on the surface for several days after heavy rain
• Rushes, sedges, horsetails, tussock grass and meadowsweet
• Pale green or yellow and unthrifty young plants
• Blue or yellow clay subsoils or panning.

There is also common agreement that vines grow best on poor soils, as:

• These restrict canopy growth (canopy management?)
• They are often stony & well-drained, leading to a high thermal conductivity