Our maritime climate is distinctly different to Auckland city just 12k away to the west. We are warmer and dryer when it matters (particularly January to April), lying in the rain shadow between the Waitakere ranges to the West and the Coromandel peninsula to the East.
Some studies have confirmed the similarity of our climate to the Medoc in Bordeaux – another distinctly maritime region. However our latitude is equivalent to the south of Spain and it is the surrounding sea that keeps our diurnal temperature range cooler and narrower.
High rainfall (irrigation not required), dry summers (no significant rainfall for 3-4 months up to harvest in most seasons), high UV and salt-laden desiccating winds off the sea (great botryitis control), are all significant factors.
According to some studies, the rock beneath the vineyard is the single most significant factor in variations of grapes and wine from site to site. The vineyard sits on the eroded and exposed core of what was once a massive mountain ridge (hence our name) composed of deep core rocks of the Upper Jurassic period about 5000 metres thick and 155 million years old. These rocks are made up of a top layer of thick, fine graded sandstones, finely bedded mudstones and silstones with magnesium nodules, argillites and thin layers of mysterious rocks called cherts composed of almost pure silica from great depths in the abyssal trench.
The thin, young, acidic, cracking clay and stony soil contains weathered Jurassic rock fragments from the core of the mountain beneath and a layer (‘pan’) of grey ash from nearby volcano Rangitoto. The soil was , low in calcium, boron and phosphate-poor, with low organic matter, but rich in iron and magnesium from the basaltic volcanic intrusions into the sedimentary base rocks below. The cracking clay soil sets hard in summer with cracks several centimetres across.
As we planted we struck 3 or 4 cm of grey volcanic ash set into a hard pan in the lower zone of the topsoil which in places had to be broken through using a heavy crowbar. This was from the nearby basaltic volcano Rangitioto which erupted many times up to about 600 years ago, burning off the native Kauri forests on the West end of Waiheke and the adjacent islands in the gulf.
Our impoverished soils are separated from the base rock by varying depths of aluminium-rich, water-retaining yellow clay. If the best wines are made in the poorest soils then we have a great foundation!
We have an intensive organic program of soil improvement with composting (picking up by hand and mulching all our pruned canes into our compost heap with marc from the winery (stems, seeds, skins and lees), together with seaweed fungal enhancers and organic lime. In addition, we promote wild pasture with wild flowers in all our rows to increase the organic matter and attract beneficial insect predators. The vineyard is managed entirely ithout irrigation (ie dry farming).