The Kenwood Press
: 05/01/2016

Fine tuning the soil to the vine

George MacLeod

Hanging on the wall in our barn there’s a black and white photo of my wife Greta and me standing proudly beside a newly planted grape vine. I noticed it again recently and thought, “My godfathers, how young we look!” We began planting this vineyard some 40 years ago. That must mean that some of our fellow travelers on this journey might be getting a little tired. No, I’m not talking about the Old Patron…I’m thinking about the vines. Almost all of our producing vines are now 30 to 40 years old. That means many parts of our vineyard will need replacement in the years ahead.

Consider all the decisions that will have to be made. Should we replace with the same grape varieties, or should we evaluate other varieties? Should we interplant to gradually phase new vines into production as older vines phase out? Or should we tear out the old and plant all anew? And much of the supporting trellis and irrigation infrastructure is showing its age. Should we repair? Or haul it all out and replace?

Plenty to think about for the future, but let me give you a status report on vintage 2016. The vines are well past bud break and the new, tender beginning canes are already two to four inches long. Upon close inspection you can see the one or two inch long clusters of tiny green berries that will become the bunches of grapes. What only months ago were hard, dormant, brown buds have burst out with shooting canes, tiny grape clusters and – my favorite – clusters of tiny green leaves that gather droplets of morning dew on their delicate pink fringe and sparkle like a diamond necklace in the low-angle morning light. Over the next few weeks, the new canes will leap out of these small clusters of leaves and grow up at a rate of two to three inches a day, until in a few weeks they will be 24 to 36 inches long. Now let’s hear a word or two about what the human members of this ranch team are doing.

Soil Resistivity

We have just completed work on plans to strengthen our soil – our most basic ranch asset – by doing a resistivity survey of the entire vineyard. We haul measuring equipment, row by row, through the vineyard. This produces a map that shows in brightly colored detail the soil resistivity levels throughout the vineyard. Soil resistivity is a measure of how much the soil resists the flow of electricity, or a measure of the capacity of the soil to transport charged ions (hence nutrients) in the soil.

How to interpret what soil types are represented by the different resistivity colors is the big issue. From our 40 years experience we know that we have different soil types across the ranch. The ranch sits atop an eroded alluvial fan, giving us a whole complex of sometimes rocky, sometimes sandy, sometimes clay soils. We have a backhoe coming to dig trenches in different areas around the vineyard, so we can get a first-hand look at the soils in the different resistivity areas.

Now with our resistivity survey we can define these different areas in the vineyard. We know from other ranches that if we can hand tune our vines to the different soil areas, we can farm in a way that takes advantage of the different soil types to produce a family of excellent wines that each takes advantage of their unique terroir. The problem is that we will have to learn how to farm a lot of relatively small areas … Stop! Did I say, “problem?” I mean the opportunity here is that we will get to take advantage of the unique variety in our soils to produce even better wines.

Back in l977, when we were still doing preliminary research on how to plant our vineyard, the various authority figures we consulted told us that we should be able to earn five to six hundred dollars per acre if we did everything right. Well after all these years we have seen nothing like that amount of money. But something nice and surprising did happen. We fell madly in love with the grapes and never did get tired or bored with working and caring for them. I feel that we do indeed know the name and address of each individual vine.