The planting zones in Indiana range from the cooler 5b in the northwest corner of the state to 7a along the southern border. This is according to the recent 2023 update of the USDA Hardiness Zone Map.
The USDA Hardiness Map is a map that divides the United States into 13 different zones by the average minimum annual temperature. Each zone spans multiple states, and each state contains multiple zones. Gardeners and farmers use these zones to determine which plants can grow in their area. Here’s more about Indiana’s growing zones:
Map of Indiana’s Planting Zones
Here’s a more detailed explanation of planting zones and how you can use them: “How to Use the Updated 2023 USDA Hardiness Zone Map.”
Zone 5b: Northwest Corner of Indiana
Zone 5b is the coolest of Indiana’s hardiness zones. This zone contains a small portion of Northwest Indiana and interestingly enough has one spot that’s detached from the rest of the zone. Zone 5b has an annual average temperature of negative 15 to negative 10 degrees Fahrenheit.
Indiana’s Zone 5b contains parts of several counties, including Montgomery, Benton, White, Jasper, Pulaski, Starke, Lake, Porter, LaPorte, and Newton. It also contains the major city of Crawfordsville, as well as parts of Crown Point and Valparaiso.
For more details, see: “Planting Zones of Northern Indiana.”
Zone 6a: Much of Northern and Central Indiana
The next coolest gardening zone in Indiana is Zone 6a, which is the largest zone in the state. 6a dominates most of Northern and Central Indiana, including the entirety of the Northern border and most of the Eastern border. 6a has an average annual minimum temperature of negative 10 to negative 5 degrees Fahrenheit.
Indiana’s Zone 6a contains numerous counties and cities. In addition to the remaining portions of the 5b counties, 6a also has counties as far north as Lagrange and as far south as Clay or Owen. In terms of cities, 6a’s range extends from South Bend to Martinsville.
Zone 6b: Much of Southern Indiana
The second largest of Indiana’s growing zones is Zone 6b. Zone 6b contains most of Southern Indiana, and just like 5b, it has a small portion detached from the rest. This zone has an average annual minimum temperature of negative 5 to 0 degrees Fahrenheit.
Zone 6b contains most of the counties and cities of Southern Indiana. Its range spans from Shelby County down to Crawford. 6b also contains the cities Bloomington, Vincennes, Washington, Jasper, Bedford, Madison, and even Indiana’s capital city, Indianapolis.
For more details, see: “Planting Zones of Southern Indiana.”
Zone 7a: Southern Indiana Border
Lastly is Zone 7a, the warmest zone in Indiana. At a minimum annual average temperature of 0 to 5 degrees Fahrenheit, it’s the only zone to reach above negative temperatures. 7a runs along most of the Southern border of Indiana and crosses over into Ohio.
In terms of counties, Indiana’s Zone 7a contains Posey, Vanderburgh, and Warrick, as well as parts of Gibson, Pike, Dubois, Perry, Spencer, Harrison, Floyd, and Clark. 7a also contains the major cities Evansville and Jeffersonville.
More Lawn Care and Landscaping Resources for Indiana
Knowing your USDA zones is far from the only way to take care of your Indiana landscape. Check out some of our other resources to learn how to care for your Indiana lawn:
When to Fertilize Your Indiana Lawn
When to Overseed Your Indiana Lawn
When to Aerate Your Indiana Lawn
The Best Time to Plant Grass Seed in Indiana
FAQ About Indiana Growing Zones
When is the growing season in Indiana?
The growing season for Indiana starts after the last frost of winter, which typically comes in late April. The season ends with the first frost of fall, which is usually early October. The exact dates for both frosts depend on your area.
What’s the best grass type for Indiana?
The best grass for Indiana depends on where in the state you live. Most are cool-season grasses like fescues, Kentucky bluegrass, and perennial ryegrass. However, some areas can also support warm-season grasses like Zoysiagrass.
Find a Lawn Professional Today
Knowing your local growing zone is very important when picking plants for your landscape. If you don’t know which zone you’re in, you may accidentally plant something that won’t survive the next winter.
Talk to an Indiana landscaping expert if you need help selecting plants for your landscape. Whether you’re in Indianapolis, Fishers, Crown Point, Lebanon – or anywhere else in the great state of Indiana – LawnStarter can connect you with passionate lawn care and landscaping pros with helpful advice.
Main Image Credit: Ken Ratcliff / Flickr / CC BY 2.0