Indiana's planting zones range from USDA Hardiness Zone 5b in the northwest corner of the state to Zone 7a along the southern border. Specifically:

• Zone 5b (average annual extreme minimum temperatures of -15 to -10°F) covers northwest Indiana, including counties like Starke, Pulaski, Jasper, and Benton

• Zone 6a (temperatures of -10 to -5°F) includes much of northern and central Indiana, including cities like South Bend and Fort Wayne in the north

• Zone 6b (temperatures of -5 to 0°F) covers much of southern Indiana and parts of central Indiana, including Indianapolis and Bloomington

• Zone 7a (temperatures of 0 to 5°F) is found along the southern border of Indiana, including counties below I-64 such as Posey, Vanderburgh (Evansville), Warrick, and Spencer

Thus, Indiana's USDA Hardiness Zones span from 5b to 7a, with colder zones in the north and warmer zones in the south

. This range helps gardeners select plants suited to their local climate conditions.