Changing climate forcing Napa Valley grape growers to tweak their technique

RUTHERFORD — In Napa Valley, grape growers are waiting for the heat wave to end to begin harvesting their crops for this year’s vintage. But one grower has developed a method of planting that may offer hope to a region that is increasingly vulnerable to climate change.

By 2 p.m. Tuesday, it was 115 degrees in Mark Neal’s Rutherford vineyard, and the day before, it was even hotter at 118. Neal has seen a lot in his 56 years of farming.

“…but I have to say that this one here is catching my attention,” he said. “Because the last time I think I saw 118 was yesterday, and the previous one was, I think, in ’77 or ’76.”

Neal began helping his dad grow grapes when he was only eight, bought his first tractor at age nine, and along the way he became something of a maverick in the valley. In 1984, he was the first grower to be “certified organic.” He also invented a system for lighting up his vineyard, pioneering the idea of harvesting grapes in the cool of the midnight hour.  

But it is his latest innovation that is drawing attention during the brutal heat wave. Along each row of his vineyard, Neal has planted two grapevines, one on top of the other.

“This vine is catching all the sun rays, 100 percent of the sun rays,” he said. “And down here, you can see where we have shade going over the fruit.”

A row of hearty Cabernet grapes on top shaded the more delicate Vermentino grapes below, protecting the white berries from sunburn and boosting their acid levels. Neal began experimenting with the technique 25 years ago and he is still the only one in Napa Valley doing it. But with vineyard land now selling for half a million dollars per acre, the idea may become appealing for another reason.

“We basically took 18 acres and made 36 acres out of it,” said Neal.

The stacked trellis system doubles the amount of production on each acre, producing two different varieties of grapes. But the amount of water and labor required is the same as a single row of vines. Climate change is wreaking havoc on weather patterns and water supplies, and Neal thinks it’s time Napa Valley started thinking outside the box.

“We have to look, as farmers, what can we do to continue our businesses here?” he said. “Will it be change of root stock, change of varietals, change of trellis systems, change of irrigation management? What are our resources going to be?”

Napa Valley is famous for its Cabernet wines, but it’s possible that climate shifts could force a change in the type of grapes that can be grown there. If that happened, Neal said the challenge would be convincing the public to embrace different varieties of wine coming from the region. In the Valley, change has been hard to accept, but change is coming; in fact, it may already be here. And Neal thinks it can no longer be ignored.

“I think we have to deal with it. There’s evidence in science that we have to deal with it,” he said. “But I have to say, as I stand here today when it’s 115 degrees, that, it’s coming, right?”