Drive by the corner of the old vineyard at Walker Ranch this spring and you’ll see about an acre of new vines. Our neighbors will certainly question why are we planting these new vines in the face of another year of drought. It’s a good question and one that deserves a clear answer.
The vines we are talking about are 40 years old. They still make good wine just far less of it. Disease has knocked them back hard the last five years and we are replacing the vineyard a few acres at a time.
We did think about whether to replant this year or wait. After careful consideration, we realized that from a water perspective the new vines would use far less water than the older mature vines.
The old vines are irrigated less frequently but for 36–hours at a time. The new vines once a week but for only a few hours. All of them are on a drip system we installed five years ago that cut our water use from the older sprinkler system by a third.
To make sure the old vines are not irrigated when they do not need it and that the new vines with the shallow roots are not irrigated too deeply, we will actually installed a second drip line. That way each plant can get what they need. No more. No less.
Our vineyard also uses very sophisticated soil moisture monitors that take readings at 1 foot, 2 feet, 3 feet and 4 feet. We only water the mature vines when the deep 4–foot reading shows that the soil is dry. As I noted, it takes about 36 hours to get the slowly dripping water that deep. They new vines will be irrigated when the 1 and 2 foot readings show the need for irrigation. We will turn them on for only a few hours.
In the end, the new vines will get in this year and start the 4–year journey to their first crop and in the interim each vine will get just the water it needs and our water use on that ace will be less during this trying time of drought.
So that’s what we will tell the neighbors as they slow and ask how the work is going and wonder aloud how much more water we will be using this year. The simple answer with the longer story answer is actually less than last year