The best vineyard soils are those that permit deep and spreading root growth and provide a moderate supply of water, released incrementally over time (Seguin, 1986). Soils to be avoided include those that are compacted and severely restrict rooting, soils that are chronically or seasonally water-logged, and soils that are extremely droughty (in the absence of irrigation).
Excess moisture leads to surplus vegetative growth, increased fruit acidity, and diluted fruit and wine flavors. At the other extreme, drought stress can lead to insufficient vine growth and reduced yields, impaired fruit ripening, and sunburning of fruit.
Source: Virginia Tech Extension