The USDA divides the United States into seven planting regions, known as hardiness zones, which were most recently updated in 2023. The maps below show these planting regions.

The treatment gives the seed a chance to germinate and grow in damp soil. It’s done much more often to vegetable seeds than flower seeds, and particularly to slow-germinating or large seeds.

In Tennessee, the state ranges in four different zones, 6a (-10 to 15 degrees Fahrenheit) in the highest altitude of the mountains to 8a (10-15 degrees Fahrenheit) in southern parts of the state.