California wine grape growing has become as “narrowingly”
uncertain as it has become more economically harrowing.  Vine
balance starts with good vineyard design. Although that seems
like a simple concept, it’s actually where things start getting
complicated, according to Jim Wolpert, Cooperative Extension
viticulture specialist, University of California, Davis.
Especially today with so many closely spaced vines where there
is so much uncertainty.  “We do not know anything about the
canopy based solely on row and vine spacing,” he told attendees
at a recent UCCE grape grower meeting in Paso Robles. “We have
soils that are all over the map, varieties that are all over the
map, and we know very little about them.”  This gap in knowledge
makes the notion of matching a rootstock to a soil very
difficult, according to Wolpert. “Ford can tell you the towing
capacity of Ford F-250, but we can’t tell you the towing
capacity of a rootstock.”  Factors such as soil fertility and
scion are givens at the onset of vineyard