Santa Cruz Mountains

Geological Influences

Certain soils in the Santa Cruz Mountains date back over a 100 million years, to the Mesozoic and Paleozoic eras. Many more are younger than that, dating back only a few million years. The activity of the Pacific and North American Plates has, over the course of hundreds of millions of years, created a place with great geologic diversity. East of the San Andreas fault one finds the ancient Franciscan Complex with its volcanics, shale, and limestone; west of the fault the terrain is Salinian, with granite and limestone soils. 

This unique geological landscape is in constant motion. Each time the two plates slide against one another, the soil compositions shift. Over the course of millions of years this constant movement has created a place rife with variation and complexity. No two parcels are the same, each having its own unique soil composition and mineral content.

Mountains/River/other key influences

The Santa Cruz Mountains are a series of ridges beginning just south of San Francisco and ending at Salinas. The mountains were formed millions of years ago, by a leftward bend of the San Andreas Fault, wherein segments of the fault began to overlap with one another. The fault line runs along the ridge throughout the entire mountain range.  

The highest point in the mountain range is the Lomo Prieta Peak, reaching nearly 3,800 feet (1,150 m). This was the epicenter of the 1989 Lomo Prieta earthquake. 

The mountain vineyards are low-yielding sites, known for producing concentrated berries, with deep color, intensity of flavor, and complexity of aromatics.  

The entire AVA is nearly 500,000 acres in size, only a small fraction of which -- less than 1% -- is planted to vine. The sheer elevation of the mountains makes planting and harvesting grapes an arduous task, so despite the quality of the wines, vineyard plantings remain relatively sparse. Many vineyards are not contiguous, which further complicates viticulture. Remaining land is rich in biodiversity, supporting a number of ecosystems, ranging from dry chaparral to cool and moist coastal forests. These ecosystems depend on native California vegetation such as redwoods, eucalyptus, and grasslands, and they are home to a large number of species of birds, as well as deer, black bears, foxes, bobcats, cougars, opossums, and rattlesnakes. 

Soil Diversity

The Santa Cruz Mountains AVA is an ancient seabed, and as the mountains formed, over the course of millions of years, these ancient soils were pushed to the surface. 

These soils include limestone, sand, clay, shale, volcanic, granite, decomposed rock, sandstone, and schist. Limestone and granite soils are often found on the Pacific side of the mountains, while the mixed Franciscan Complex is abundant east of the mountains. The abundance of minerals like cinnabar, talc, gypsum and graphite impart a strong mineral character to the wines. 

Near the tops of the ridges, the soil complexity is greatest, and multiple grape varieties might be planted within just a few feet of each another, each one best suited to its specific microclimate. This, above all, illustrates the unique diversity and utter confusion of the Santa Cruz Mountains AVA.

Climate

The overall climate of the Santa Cruz Mountains is cool Mediterranean, a Region on the California Heat Summation Index; however, within the AVA one finds greater climatic diversity. The western side of the mountain benefits fully from its proximity to the Pacific Ocean. The lower elevation sites are enveloped by fog, which help vines maintain a steady, cool temperature. Above the fog line the grapes are safe from the mold and rot that can happen in moist conditions. These higher elevation vineyards benefit from more direct sunlight which is offset by an even stronger diurnal variation. As a result, these vineyards enjoy a long growing season, with harvest occurring in early autumn and ending before the rain begins. Rainfall usually occurs during the late fall/winter and is generally around 50 inches (127 cm) per year. 

The eastern side of the mountains has different conditions. The sheer elevation of the mountains creates a rain shadow effect, preventing the cool Pacific air and wet weather from traversing the mountain. The San Francisco Bay acts to moderate temperatures on the eastern side of the mountain ranges, but there is far more warmth and sun -- and far less rain --  on the eastern side, with an annual rainfall of only 11 inches (28cm). 

Pinot Noir and Chardonnay are generally planted on the western side of the mountains, while Cabernet Sauvignon, Merlot and Zinfandel are planted on the eastern side of the mountains.