John Thull

John Thull

Vineyard Manager

University of Minnesota - Horticulture Research Center

600 Arboretum Blvd.
Excelsior, MN 55331

Cell Phone: 320-333-0115
Office Phone: 612-301-1827



Course(s): VIN 117 - Cold Climate Viticulture and Enology

John Thull and his wife Jenny manage the 10 acres of research vineyards for the Grape Breeding Program at the University of Minnesota’s Horticultural Research Center (HRC). They started in 2005 and 2008, respectively. The vineyards contain plantings of thousands of novel seedlings that are continually evaluated for cold hardiness, disease tolerance, growth habit, productivity, and fruit quality for wine production or fresh eating. Several species of wild grapes, a vast collection of French, American, and cold hardy hybrids, and numerous Vitis vinifera cultivars are grown on-site to provide the genetic diversity needed to create the classically bred crosses. Growing so many different vines under one roof is quite challenging, but extremely interesting. Aside from grapes, John and Jenny also grow over 270 varieties of pumpkins, squash, and gourds on several research plot acres which are displayed at the Minnesota Landscape Arboretum every October.

After earning his degree in Biology in 2002 at the U of M in Duluth, John apprenticed in Germany at Weingut Heinrichshof. This family-owned winery with 5 acres of vines is located in the idyllic village of Zeltingen nestled in the narrow and winding Mosel River valley. Famous for its steep, Riesling vineyards, this region experienced stellar vintages in 2003 and 2004 while he was there.

John’s fondness for viticulture stems from his childhood on the farm where he learned how to garden with his grandmother and harvest wild grapes with his family and friends to make juice and homemade wine. In 2007, he planted 2 acres of vines at the family farm near Melrose, Minnesota. John has gained invaluable experience from tending both these vines and those grown at the HRC.

Over the past several years, John has shared his knowledge through talks, presentations, and in-field clinics to grower groups in MN, WI, IA, IL, ND, CO, NH, and VT. Every season presents different challenges to growers of cold hardy grapes. John enjoys trying to find the right combination of management techniques needed every year to handle these challenges.