Madeline Wimmer, Extension Educator, Fruit Crops Images: The new 2023 USDA Plant Hardiness Zone Map for Minnesota (left) and previous from 2012 (right). The United States Department of Agriculture (USDA) plant hardiness zone map is a tool based on average annual extreme winter temperatures that can help growers determine which plants can survive the winter and thrive in a given region. Zones are represented by a number scale from 1-13, separated by 10°F increments, with larger numbers being warmer than smaller numbers. Each zone is then divided into two half zones, ‘a’ and ‘b’, with ‘a’ having 5°F colder average extreme winter temperatures than ‘b’. Both plant species and cultivars (i.e., cultivated variety) vary in zone hardiness. For example the wine grape cultivar ‘Petite Pearl’ is listed by the Minnesota Department of Agriculture (MDA) to be hardy in Zone 4 regions, whereas ‘Concord’ should be grown in Zone 5 or higher and will have lower chances of surviving in colder hardines