Geography, Soils & Climate
McLaren Vale has many subregions that producers reference, such as Blewitt Springs, McLaren Flat, Seaview, Sellicks and Willunga, but these are not enshrined in law, with as many as 19 posited by the McLaren Vale Grape Wine & Tourism Association, who produced a detailed geological map of the region in 2010. The established subregions are both distinct from each other and far from homogenous within themselves. The Vale is said to have over 40 distinct geologies, with the oldest dating back 500 million years, and the youngest a mere 15,000-year-old pup. Red-brown sandy loams, grey-brown loamy sands, distinctly sandy soils, patches of red or black friable loams and yellow clay subsoils interspersed with lime are all part of the picture.
McLaren Vale is characterised by a Mediterranean climate with hot summer days and low rainfall in the growing season, making it particularly resilient to disease pressure. That warmth and lack of humidity no doubt has been a great aid in the Vale being able to establish the most certified organic vineyards of any region. Those warm days are meliorated by cooling breezes from the Gulf of St Vincent and air filtering down from the flanking Mount Lofty Ranges, while typically good winter and spring rains set the vines up for the coming season. While some vineyards are dry grown (about a fifth), a reclaimed water network accounts for the irrigation requirements, making McLaren Vale viticulture sustainable without employing groundwater or river water resources.
