In conjunction with the Northeast Regional Research project NE-1020 “Multi-state evaluation of wine grape cultivars and clones,” Iowa State University established a cold hardy wine grape cultivar trial in 2008 at the ISU Horticulture Research Station (HRS), Ames, Iowa, and Tabor Home Vineyards and Winery (THV), Baldwin, Iowa.
The recent release of interspecific hybrid grape cultivars that are hardy for the northern climates of the United States has led to a rapid expansion of the grape and wine industry in the Upper Midwest, as well as other cold-climate regions. These cultivars often exhibit high vegetative vigor and possess fruit quality concerns when their grapes are to be used in wine production.
The use of herbicides in vineyards has been a cost-effective means of in-row weed management under the grape canopy. However, as public concerns about issues such as pesticide run-off, ground water quality, and soil erosion have increased, grape growers have become aware of a need for alternative methods of weed management.
The Iowa wine and grape industry underwent a rapid phase of growth at the turn of the 21st century that is continuing to evolve and develop today. Cultivar trials across the state found that `Marquette' grapevines were performing poorly in eastern Iowa while other cultivars performed well. A preliminary investigation suggested a magnesium induced potassium deficiency and/or above optimum soil pH as the cause of poor growth of `Marquette'.