Sonoma Mountain Soil & Terrain
The Effect of Sonoma Mountain Soil on Grape Growing
The terrain of Sonoma Mountain is largely made of debris from the Sonoma Volcanics. Millions of years ago, several nearby volcanoes sprinkled the region with a layer of volcanic ash. This ash has decomposed and eroded to varying degrees and is currently responsible for the different soils on Sonoma Mountain.
There is a significant amount of basalt and other volcanic rocks in the ground. Many of these rocks are porous from gases released when they were molten. The lava flowed over the region very fast, creating shield rather than more conspicuous cone volcanoes. The result is lower hills with a broader base.