The Crush - October 2019 - 1

Volume 46 Issue 10 October 2019


Adapting Vineyards to Climate Change

By Ted Rieger
California has experienced an increase in minimum, maximum
and average temperatures based on weather data from pre-1900 to
the present, and trends in temperature increases related to climate
change are expected to continue. The following are examples
of grape growing counties with average annual temperature
(Fahrenheit) increases based on 1895-2018 weather data from the
U.S. National Oceanic and Atmospheric Administration: Napa
+2.3 degrees, Sonoma +2.1 degrees, Mendocino +1.9 degrees, Lake
+1.5 degrees, and Santa Barbara +4.2 degrees.
Extreme heat impacts crop phenology, and for winegrapes,
can impact the chemistry and development of phenolics and
sugars that affect wine quality. Temperature increases not only
result in daytime growing season heat waves, overnight low
temperatures have also increased affecting diurnal temperature
shifts important for fruit development and quality. Warmer
winters and reduced winter chill hours during dormancy are
also concerns for vine and tree crops that can affect development
stages and timing of flowering and fruit set.
California grape varieties and premium varietal wines that could
be most immediately affected by climate change are cabernet
sauvignon and pinot noir. Alternative grape varieties are
available and are being grown in warmer regions for premium
varietal wines and for blended wines at multiple price points.
Mark Battany, University of California Cooperative Extension
(UCCE) water management and biometeorology advisor for San
Luis Obispo and Santa Barbara counties, presented the following
winegrape adaptation strategies for a 2018 California
Department of Food and Agriculture (CDFA)
webinar ("Exploring On-farm Climate
Change Adaptation Strategies"):

Placing shade cloths over vine canopies and fruit zones can mitigate growing
season heat spikes related to climate change. Photo: Ted Rieger

* Choose adapted winegrape varieties based on site climate
* Select the microclimate with the trellis system: consider row
orientation, trellis height, and the effect of canopy management
on shading fruit.
* Modify the microclimate by using shade cloths, reflective foliar
sprays (kaolin, CaCo3), vineyard floor management, and the
use of sprinklers/misters during high heat events.
With 99 percent of Sonoma County vineyard acreage now
certified sustainable, Sonoma County Winegrowers (SCW)
recently announced a new initiative to participate in the
California Land Stewardship Institute's Climate Adaptation
Certification Program. It will be the first such third-party
certification program designed specifically for vineyards.
Initially, 20 Sonoma County vineyards will participate in a pilot
program to evaluate current practices and implement new
practices to reduce greenhouse gas (GHG) emissions of carbon


The Crush - October 2019

Table of Contents for the Digital Edition of The Crush - October 2019

The Crush - October 2019 - 1
The Crush - October 2019 - 2
The Crush - October 2019 - 3
The Crush - October 2019 - 4
The Crush - October 2019 - 5
The Crush - October 2019 - 6
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The Crush - October 2019 - 9