Mt. Veeder, which lies to the south of Spring Mountain, contains mostly older sedimentary soils. Diamond Mountain, which lies to the north, contains soils of newer volcanic origin. Spring Mountain is a mixture of volcanic and sedimentary soils, leaning more toward the latter. Often we find the younger volcanic soils cut by erosion to reveal the sedimentary soils below.
At an individual site and slope, these distinctions have various implications, but the most important thing about the soils on Spring Mountain is that they are what we call residual upland soils. These soils are not deep, they are not rich, and they are generally more stressful to the vine. These soils limit its growth and root structure.
Whatever the soil on Spring Mountain, you usually find it on a slope. (At Spring Mountain Vineyard, the flattest vineyard block is about a 10 % slope. The average over the 226 acres is about 25%.) This encourages water to drain from the soils and adds to the stressful nature of the vineyard site.
Contrasting these stressful upland soils on Spring Mountain, on the valley floor we find deeper, sometimes rich alluvial soils that hold a more moisture. Valley floor vineyards are flat to gently sloping. Grape vines on the valley floor look different. They are bigger and more vigorous.