The volcanic history of the Bennett Valley landscape is outlined by the stone walls of eroded lava and tuff that crisscross its farms, pastures and vineyards. This rocky array of volcanic cobbles predicts the common characteristic of Bennett Valley’s vineyard soils: good drainage. Grape vines in the valley have long cool summers to ripen, and the steep rocky slopes are a perfect medium to encourage deep roots and deep flavors without dilution.
On the slopes of the foothills, soils are primarily of volcanic origin (Goulding-Toomes-Guenoc Association) and include lava flow, tuff beds and sandstone, gravel and some conglomerate. The lower slopes and valley floor soils offer more variety, including some of alluvial origin. Spreckels loam is distributed throughout the region.