Derived from fossilized sea life and transported as alluvium, Santa Rita Hills' soils are similar to those found in Champagne, Chablis and the Cote D'or. These soils are essential for the age-worthy and stunning Chardonnay that comes from each of these regions. While Calcium via chalk and limestone supplies the minerality that shines through in France, it is Calcium Silicate (aka; Silica) by way of Diatomaceous Earth that does the trick here. Diatomaceous earth, the parent material for the major soil types within the Sta. Rita Hills AVA, is made up of Diatoms (the skeletons of ancient sea creatures). Combined with the alluvial nature of these ancient Sandy Loam soils, SRH provides the perfect storm for acid-retaining, mineral-rich Chardonnay.
Sandy Loam soil is composed of approximatley 60% sand, 15% silt, and 15% clay. These soils retain the optimal amount of water and plant essential nutrients, also allowing for rapid internal soil water movement. The combination of different Sandy Loam soil types in the SRH AVA is ideal for growing grapes of excellent quality.
Loam soil, dubbed the quintessential and ideal soil, is composed of roughly 40% sand soil, 40% silt soil and 20% clay soil. Loam tends to be a courser soil. Loam soil with more clay is called clay loam soil and loam soil with more sand is called sand loam soil. The combination of different soil types creates an excellent soil for cultivation. Loam soil ideally, due to the clay percentage, retains just the right amount of water and nutrients, and due to the sand percentage, drains the right amount of water—making loam soil one of the easiest soils with which to work.
Diatomaceous earth (i.e., fossil marine skeletons) is readily available as the soil parent material throughout the SRH. Composed of white porous rock high in Calcium Silicate (aka; Silica) a mineral with higher porosity than both chalk or limestone. In conjunction with the cool coastal climate within the SRH AVA, grapes grown in this environment exhibit soil minerality in the wine that we can actually taste. Wikipedia Natural News
Santa Rita Hills AVA soils-related text kindly edited by Nikki's former Cal Poly Professor:
Thomas J. Rice, Ph.D., C.P.S.S.
Certified Professional Soil Scientist No. 1932
5127 E Silver Lake Rd
Laona, WI 54541
Cell: (715) 889-9401