NARROW GATE VINEYARDS’ SOILS

Our Soils come from a series called Josephine. They consist of well drained soils that are underlain by vertically titled schists, slates and contact metamorphic rocks at depths of 40-60 inches. These soils are gently rolling to very steep ranging from 5-30% on our property. Our vineyards are planted up on slopes as steep as 15% in our Syrah and Zinfandel blocks.

1) Zinfandel – Planted on a southwest facing hill on 6X11 spacing on Vertical Shoot Positioning (VSP) trellis.

     The main type of rock found on this site is Serpentine. The rocks and soils are formed from weathered volcanic (utramafic) rocks. These soils provide a harsh environment for plant growth. Several factors contribute to the inhospitability of  serpentine soils to plant growth including:  1) a low calcium-magnesium ratio; 2) lack of essential nutrients such as nitrogen, potassium, and phosphorous; and 3) hight concentrations of heavy metals (mineral toxicity).  Serpentine is a major rock forming mineral and is found as a constituent in many metamorphic and weather igneous rocks.  It often colors many of these rocks to a green color and most rocks that have a green color probably have serpentine in some amount.  Serpentine can be an attractive green stone that takes a nice polish and is suitable for carving.  It has been used as a substitute for jade and is sometimes difficult to distinguish from jade, a testament to the beauty of finer serpentine material.

2) Viognier and Grenache – Planted on south facing hills on 6 X 9 spacing on VSP trellis.

    The rocks and soils are named Rhyolite, also known as Placerite.  Rhyolite is usually light grey to pink in color, and it can form in two different ways.  The most spectacular way to form rhyolite is to have a very explosive eruption which hurls hot lava and fragments of the volcano into the atmosphere.  Gravity eventually brings these pyroclasts back down to Earth’s surface where they are deposited as layers.  If the pyroclasts are hot enough, they might weld together to form a rock called rhyolite tuff, in which we have TONS!!

3) Syrah – planted along the crest of the highest part of our property with a slight southeastern slope on one side and North Slope on the other.  Spacing is 6’ X 10’ on VSP trellis.

     These rocks and soils are called granites and meta-sedimentary rocks such as schist.  The meta-sedimentary rocks are older:  they were originally sediments deposited in marine environments during early Palaeozoic times (~ 570 – 400 Ma ago).  These deposits of mud and sand were probably thousands of meters thick, and deposited in subsiding basins.  Later, as they became involved in intense folding and heating during mountain building, the mineral composition of these rocks was changed by heat and pressure.  The clays in the mud rocks changed to mica, forming a characteristic sheen on folded surfaces in the resulting metamorphic rock:  schist.

4) Mourvedre and Roussanne – planted just below Syrah on the same type of orientation on 6 X 10 VSP trellis.
    
    This site is the roughest, most diversified and most inhospitable of all our sites.  If the shallow soils (due to the many rocks!) don’t do these guys in, the gophers, turkeys or birds will.  It is the most remote locale and bordered by trees to the South and the West, with a large, open hillside on the North (great for varmints to hide in!).  The main soil type is similar to Syrah with meta-sedimentary rock, however there are many floating (above ground) rocks filled with quartz and quartzite.  Some of quartz is Rose Quartz, but the majority is the milky white quartz.  Quartz is the most common mineral on the face of the Earth.  It is found in nearly every geological environment and is at least a component of almost every rock type.  It frequently is the primary mineral, >98%.  It is also the most varied in terms of varieties, colors and forms.  This variety comes about because of the abundance and widespread distribution of quartz.