The Walla Walla Valley experiences the most extreme climatic conditions among Oregon’s wine regions. While production systems have adapted over time, climate change has led to more unpredictable and intense weather. These shifting conditions — combined with the broader impacts of global climate change — demand new approaches to sustainable agriculture.
To address these challenges, the Oregon State University Extension Service horticulture program in Umatilla County developed a multi-faceted applied research and education program focused on sustainability and climate resilience in grape production.
These research efforts help local growers respond to climate challenges while improving production sustainability.
One major initiative began in 2022 with a pilot study on the use of kaolin clay in vineyards. Kaolin, already used in local orchards to reduce heat stress and sunburn, showed promise for grape production. A local grower and winemaker in Milton-Freewater hosted the initial trial in a commercial syrah block.
Based on early success, the project received funding from the Agricultural Research Foundation to expand the research through 2025. In 2023, additional trials were launched to fine tune application methods and evaluate kaolin’s potential benefits for insect management, wildfire smoke exposure and wine quality. Throughout the season, kaolin was applied multiple times to maintain canopy coverage, with researchers monitoring vine stress, yield and fruit quality.
Results showed that kaolin-treated vines had higher yields and better fruit quality compared to untreated control plots. The study also demonstrated reduced heat and light stress on leaves. Wine produced from the trial vineyard is being evaluated for quality and will be used for future outreach to growers in the valley.
The kaolin project concluded in 2024. Findings were presented to local, state and national audiences, including at Walla Walla Grape Day and the American Society for Enology and Viticulture National Conference. Initial results were also published in the American Journal of Enology and Viticulture.
In 2023, OSU Extension launched a second major research project to support regional sustainability — a cover crop study funded by Western SARE (Sustainable Agriculture Research and Education), a program of the U.S. Department of Agriculture. Running through 2026, the project aims to increase the use of cover crops in vineyards to improve soil health and grape quality.
The project involves collaboration with several local growers, multiple research trials and targeted education. It also addresses unique barriers to cover crop adoption in the Walla Walla Valley, such as water availability and timing of vineyard operations.
Together, these research efforts help local growers respond to climate challenges while improving production sustainability. Through science-based trials, grower partnerships and shared learning, OSU Extension supports a more resilient future for the region’s wine grape industry.
