Geography, soils & climate
The Yarra Valley has a great geological and geographic diversity, though there are some helpful generalisations that make it navigable for the newcomer. Broadly divided into the Lower and Upper Yarra, based on the flow of the Yarra River (east to west) from its source in the Yarra Ranges down to the flatlands, which then extends into Melbourne and the bay. The Lower Yarra is accordingly lower in elevation, producing wines with a typically sunnier, more fruit-rich profile, while the Upper Yarra can tend to the quite lofty, with many of the more elevated sites originally marked for sparkling wine production.
The soils, though deeply nuanced, also fit into two broad categories, with the northern side of the valley (the Lower Yarra) tending to duplex soils consisting of grey loamy sand to clay loam with red-brown clay subsoils, which are low in fertility, while the southern part (the Upper Yarra) is more characterised by deep-red volcanic soils, which are very fertile. Within these broad types, there are varying degrees of difference, as well as a couple of notable sites that deviate entirely, with granite being the predominant influence.
The climate of the Yarra is overwhelmingly cool, though naturally the valley floor is warmer than the more elevated sites. While the climate is classified as continental, there is not the typical diurnal temperature difference, with the Southern Ocean still providing some moderation. Rainfall is largely concentrated over the spring and winter months, with a relatively dry growing season, typically necessitating irrigation. The Upper Yarra has higher rainfall than the Lower Yarra.
