How deep does sand have to be to defeat phylloxera in order to grow vines on their own roots?
Something I’ve been thinking about since seeing Joel Peterson (Zinfandel master, founder of Ravenswood, owner of Once & Future) speaking about Oakley Road Vineyard.
This is a Zinfandel vineyard planted on its own roots more than 100 years ago. The surface of the vineyard is sand washed down from Gold Rush mining and deposited by flooding of the Sacramental River.
Thus it’s a layer of sand on soil, and presumably roots find sustenance and water from soil below the sand.
So, if a vineyard wanted to plant own-rooted vines and dug a trench filled with sand along the line of where the vines were to be planted, how deep and wide would the sand trench have to be to protect vine roots from phylloxera?
See Joel Peterson talk about Oakley Road vineyard 34-38 minutes into the TWS recording of last week’s talk here