Grape
Growing
All
our vines are trellised using a VSP (vertical shoot positioning)
configuration and are planted in a 9' x 5' row x vine spacing grid. This
T-shaped vine geometry involves a 3' high vertical trunk, two opposing
horizontal side-arms (called cordons) on each of which about half
a dozen vertical spurs (short stubs with 2 buds on each) are located
and from which 4 green shoots grow vertically (2 per bud) and near
the bottom of which the grapes will grow. In the winter & spring
following harvest these shoots will be eventually pruned back so
as to again leave 2 buds on each spur and the cycle will start all
over again.
Frost
protection measures are required due to the late spring frost risks
mentioned above. We use a pruning method called double-pruning
where the first pass, done in winter, leaves foot-long canes rather
than the usual short 2-bud spurs. The ruse behind this approach
makes use of the fact that bud break first happens near the end of
cut canes and this delays bud break for the 2 buds of interest closest
to the cordon by up to a couple of weeks, at which point the over-long
spurs are cut back just above these 2 buds. An overhead sprinkler
system (same idea as in Florida's orange groves, using the insulating
properties of a thin layer of ice) can also be utilized as well as
spraying of a product called Frostshield, also forming a thin insulating
layer over the buds.
Pierce disease
and phylloxera which have caused ravages in the rest of the state are practically
non-existent here (only one case of phylloxera reported and no Pierce disease). An
8' fence surrounds the vineyard to protect it against the large deer population
in the area. Another animal threat comes from gophers and special control
measures are needed to control their impact. Mildew control is done using
weekly or bi-weekly sulfur applications up to veraison (when grape color changes
from opaque green to blue/purple or translucent gold - a truly magical moment)
and herbicide is applied twice a year. Mowing passes are also done at
the beginning of the season, until it gets too dry and brush fire risks get
too high.
Irrigation
water comes from NID water (19th century ditch network collecting/channeling
melting Sierra waters and originally used for mining operations). This
water is sold to us by the miner's inch, which is the size of the pipe opening
we use to tap into the nearest NID ditch located about 200' higher than our
property and providing more than adequate rates & pressure. Irrigation
is carefully controlled so as to not over water vines which makes vegetative
growth too vigorous at the expense of fruit growth (can actually impart a vegetative
character to grapes). Mature vines are even water-stressed during part
of their growing season, again to ensure a vegetative/fruit balance optimal
for the production of top quality grapes.
 To keep
the leaf canopy open (reduces mildew risks and increases sun exposure), various
green shoot/leaf pruning/tipping passes are done throughout the summer to remove
lateral shoots and limit the vertical growth of the main shoots. The
trick here is to keep just enough leaves for the photosynthesis activity level
required to ripen the fruit. Fruit in excess of the desired crop level
is also dropped as soon as formed.
Although
a mature vine can produce well in excess of 25 pounds (and even up to 50 pound
for head pruned vines) of low quality grapes if left on its own, the above
measures limit the crop level to the 5-10 pounds range per vine to concentrate
flavors/aromas and ensure the production of top quality grapes.
|
