USDA zone 6a in Indiana
USDA plant hardiness zone 6a covers 74 locations across Indiana (average annual extreme minimum −10 to −5 °F): Albany, IN, Ambia, IN, Anderson, IN, Angola, IN, Attica, IN, Berne, IN, and 68 more. Average last spring frost across this group ranges April 9 (Scotland) to May 2 (Fort Wayne), and growing seasons run 159–202 days (Fort Wayne to Scotland) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Indiana location's own frost dates; the printable planting calendar uses Delphi, this group's median-season location.
- USDA zone
- 6a−10 to −5 °F
- Last frost range
- Apr 9–May 2avg, 32°F
- First frost range
- Oct 10–Oct 31avg, 32°F
- Growing season range
- 159–202days
Locations in this group
Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|
| Albany | Redkey, Parker, Ridgeville, Farmland | Farmland 5 Nnw | Apr 25 | Oct 16 | 173 |
| Ambia | — | Boswell 4wnw | Apr 25 | Oct 13 | 169 |
| Anderson | Pendleton, Lapel, Alexandria, Daleville, Chesterfield, Frankton, +3 more | Anderson Sewage Plt | Apr 19 | Oct 23 | 186 |
| Angola | Fremont, Hamilton, Ashley, Clear Lake, Orland, Pleasant Lake, +2 more | Angola | Apr 30 | Oct 16 | 167 |
| Attica | West Lebanon, Newtown, Mellott | Attica 2e | Apr 22 | Oct 17 | 176 |
| Berne | Geneva, Monroe, Willshire, Bryant, Petroleum | Berne Wwtp | Apr 23 | Oct 22 | 181 |
| Bluffton | Ossian, Markle, Liberty Center, Uniondale, Craigville | Bluffton 6n | Apr 24 | Oct 20 | 179 |
| Bremen | Walkerton, Osceola, North Liberty, Wyatt, Lakeville, Gilmer Park, +1 more | Lakeville | May 1 | Oct 13 | 163 |
| Clarksburg | — | Greensburg | Apr 15 | Oct 26 | 194 |
| Coalmont | Jasonville, Farmersburg, Hymera, Shelburn, Midland, Clay, +1 more | Shakamak Sp | Apr 14 | Oct 26 | 193 |
| Columbia | Albion, Wolflake, Churubusco, South Whitley, Liberty Mills, Arcola, +2 more | Columbia City | Apr 27 | Oct 17 | 171 |
| Connersville | Brookville, Liberty, Metamora, West College Corner, Laurel | Brookville | Apr 20 | Oct 21 | 182 |
| Cordry Sweetwater Lakes | — | Columbus | Apr 11 | Oct 25 | 195 |
| Decatur | Monroeville | Decatur 1 N | Apr 23 | Oct 19 | 178 |
| Delphi * | Norway, Yeoman | Delphi 2 N | Apr 22 | Oct 17 | 179 |
| Elkhart | Goshen, Nappanee, Dunlap, Bristol, Wakarusa, Osceola | Goshen 3sw | Apr 26 | Oct 21 | 175 |
| Elwood | Summitville, Windfall | Elwood | Apr 24 | Oct 18 | 175 |
| Fort Wayne | Auburn, Huntertown, Kendallville, Leo-Cedarville, Waterloo, Butler, +7 more | Garrett 1 S | May 2 | Oct 10 | 159 |
| Fort Wayne | New Haven, Hoagland, Roanoke, Hessen Cassel, Zanesville, Arcola | Ft Wayne Intl Ap | Apr 24 | Oct 21 | 178 |
| Frankfort | Mulberry, Rossville, Kirklin, Colfax, Michigantown | Frankfort Disposal | Apr 21 | Oct 21 | 181 |
| Gary | Hammond, Tinley Park, Frankfort, Schererville, East Chicago, St. John, +28 more | Park Forest | Apr 23 | Oct 20 | 179 |
| Gary | Portage, Chesterton, Lake Station, Beverly Shores, Wheeler | Indiana Dunes Nl | Apr 22 | Oct 27 | 188 |
| Goshen | Middlebury, Ligonier, Syracuse, Topeka, New Paris, Millersburg, +1 more | Goshen Muni Ap | Apr 28 | Oct 19 | 171 |
| Greencastle | Cloverdale, Putnamville, Fillmore, Harmony, Coatesville, Amo, +3 more | Greencastle 1 W | Apr 27 | Oct 15 | 169 |
| Greenfield | Fortville, Ingalls, Maxwell, Charlottesville, Carthage, Gwynneville, +1 more | Greenfield | Apr 19 | Oct 22 | 185 |
| Grissom AFB | Flora, Burlington, Walton, Cutler, Camden, Lincoln, +2 more | Young America | Apr 25 | Oct 17 | 174 |
| Harlan | Woodburn | Woodburn 3n | Apr 27 | Oct 19 | 174 |
| Hartford | Eaton, Upland, Montpelier, Dunkirk, Keystone, Pennville, +2 more | Hartford City 4 Ese | Apr 22 | Oct 22 | 181 |
| Huntington | Warren, Andrews | Huntington | May 1 | Oct 14 | 166 |
| Indianapolis | Carmel, Fishers, Noblesville, Westfield, Lawrence, McCordsville, +1 more | Carmel 3 E | Apr 21 | Oct 21 | 183 |
| Indianapolis | Avon, Brownsburg, Danville, Pittsboro, Clermont | Indianapolis Eagle Creek Ap | Apr 12 | Oct 29 | 198 |
| Indianapolis | Greenwood, Whiteland, New Palestine, Pleasant View | Indianapolis Se Side | Apr 20 | Oct 21 | 183 |
| Jonesville | — | Seymour 2 N | Apr 16 | Oct 21 | 187 |
| Kokomo | Greentown, Russiaville, Cassville, Hemlock, Forest, Sharpsville, +1 more | Kokomo 3 Wsw | Apr 27 | Oct 18 | 174 |
| Lafayette | West Lafayette, Dayton, Buck Creek | Lafayette Purdue Univ Ap | Apr 26 | Oct 18 | 173 |
| Lagrange | Rome, Shipshewana, Ontario, Wawaka, Adams Lake, Mongo | Lagrange | Apr 26 | Oct 21 | 176 |
| Lizton | Advance, North Salem | Jamestown 2 E | Apr 23 | Oct 19 | 178 |
| Logansport | Idaville, Mexico, Burnettsville, Twelve Mile, Royal Center, Onward, +1 more | Logansport Cicott St | Apr 20 | Oct 23 | 185 |
| Marion | Gas, Fairmount, Landess, Sweetser, Converse, La Fontaine, +3 more | Marion 2 N | Apr 26 | Oct 20 | 175 |
| Merrillville | Hobart | Valparaiso Wtr Wks | Apr 22 | Oct 25 | 185 |
| Michigan | La Porte, New Buffalo, Fish Lake, Three Oaks, Rolling Prairie, Kingsbury | Laporte | Apr 19 | Oct 27 | 191 |
| Morristown | Carrollton, London, Boggstown | Shelbyville Muni Ap | Apr 14 | Oct 23 | 191 |
| New Castle | Spiceland, Hagerstown, Middletown, Cambridge, Sulphur Springs, Dublin, +10 more | New Castle 3 Sw | Apr 27 | Oct 17 | 173 |
| North Manchester | — | N Manchester Wwtp | Apr 26 | Oct 19 | 174 |
| Otterbein | Battle Ground, Brookston, Oxford, Montmorenci, Pine | W Lafayette 6 Nw | Apr 26 | Oct 12 | 169 |
| Plainfield | Bargersville, Mooresville, Clayton | Indianapolis | Apr 15 | Oct 26 | 193 |
| Plymouth | Argos, Culver, Bourbon, Donaldson, Tyner | Plymouth | Apr 25 | Oct 21 | 178 |
| Portland | Fort Recovery, Salamonia | Portland 1 Sw | Apr 28 | Oct 15 | 171 |
| Ragsdale | — | Vincennes 5 Ne | Apr 11 | Oct 26 | 197 |
| Rensselaer | Mount Ayr | Rensselaer | Apr 23 | Oct 18 | 177 |
| Reynolds | Chalmers | Chalmers 5 W | Apr 25 | Oct 17 | 173 |
| Richmond | Centerville, New Paris, Webster, Williamsburg, Milton, Fountain, +5 more | Richmond Wtr Wks | Apr 24 | Oct 20 | 180 |
| Rochester | Leiters Ford, Tippecanoe, Akron, Fulton, Macy | Rochester | Apr 23 | Oct 21 | 180 |
| Rockville | Newport, Montezuma, Bloomingdale, Hillsdale, Rosedale, Mecca, +4 more | Rockville | Apr 30 | Oct 12 | 164 |
| Rushville | Arlington, Milroy, Homer, Manilla, Glenwood, Mays | Rushville | Apr 19 | Oct 23 | 185 |
| Scotland | — | Crane Nsa | Apr 9 | Oct 31 | 202 |
| Shadeland | Dayton, West Point, Romney, Stockwell, Linden, Clarks Hill, +2 more | Lafayette 8 S | Apr 20 | Oct 20 | 182 |
| Shelbyville | Waldron | Shelbyville Sewage Plt | Apr 17 | Oct 22 | 187 |
| South Bend | Granger, Mishawaka, Niles, Buchanan, New Carlisle, Ardmore, +4 more | South Bend Michiana Rgnl Ap | May 1 | Oct 19 | 170 |
| Spencer | Poland, Bowling Green, Patricksburg, Gosport, Coal, Eminence, +1 more | Spencer | Apr 20 | Oct 20 | 180 |
| Star | Leiters Ford, Kewanna, Hartz Lake | Winamac 2sse | Apr 25 | Oct 18 | 173 |
| Terre Haute | Brazil, Knightsville, Fontanet, Shepardsville, Seelyville, Center Point, +5 more | Terre Haute Hulman Rgnl Ap | Apr 16 | Oct 18 | 183 |
| Terre Haute | St. Mary of the Woods | Terre Haute Indiana State | Apr 15 | Oct 19 | 187 |
| Thorntown | Advance, Ladoga, Roachdale, Darlington, Hillsboro, New Ross | Crawfordsville 6 Se | Apr 27 | Oct 12 | 167 |
| Tipton | Sheridan, Cicero, Hobbs, Arcadia, Atlanta, Goldsmith, +1 more | Tipton 5 Sw | Apr 23 | Oct 17 | 174 |
| Trafalgar | Foxcliff Estates, Monrovia, Brooklyn, Eminence, Paragon | Martinsville 2 Sw | Apr 24 | Oct 15 | 173 |
| Tunnelton | — | Oolitic Purdue Ex Fm | Apr 20 | Oct 20 | 181 |
| Valparaiso | Westville, Shorewood Forest | Wanatah 2 Wnw | Apr 29 | Oct 13 | 166 |
| Versailles | — | N Vernon 2 Ese | Apr 21 | Oct 21 | 180 |
| Wabash | Peru, Laketon, Somerset, Lagro, Roann, Urbana, +2 more | Wabash | Apr 23 | Oct 21 | 181 |
| Warsaw | Winona Lake, Milford, Pierceton, North Webster, Hoffman Lake, Mentone, +3 more | Warsaw | Apr 28 | Oct 18 | 170 |
| Winchester | Union, Lynn, Modoc | Winchester Airport 3 E | Apr 20 | Oct 21 | 183 |
| Yorktown | Muncie, Selma, Royerton, Gaston, Cowan, Oakville | Muncie Delaware Co Ap | Apr 16 | Oct 25 | 190 |
| Zionsville | Lebanon | Whitestown | Apr 21 | Oct 20 | 180 |
* Delphi is this group's median-season location — the calendar below is computed from its data.
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Planting calendar (Delphi, representative)
Computed from Delphi's average frost dates — the median-season location in this Indianazone 6a group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Feb 25 – Mar 11 | Apr 29 – May 6 | Jun 28 – Jul 18 | — | matures comfortably |
| Pepper | Very tender | Feb 11 – Feb 25 | May 6 – May 13 | Jul 5 – Aug 4 | — | matures comfortably |
| Cucumber | Tender | Mar 25 – Apr 1 | Apr 29 – May 6 | Jun 18 – Jul 8 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | Apr 29 – May 6 | Jun 13 – Jun 28 | — | matures comfortably |
| Bush bean | Tender | — | Apr 29 – May 6 | Jun 18 – Jun 28 | Aug 18 – Aug 28 | matures comfortably |
| Sweet corn | Tender | — | Apr 22 – May 6 | Jun 21 – Jul 21 | — | matures comfortably |
| Basil | Very tender | Mar 11 – Mar 25 | Apr 29 – May 6 | May 29 – Jun 13 | — | matures comfortably |
| Lettuce | Half-hardy | Mar 11 – Mar 25 | Mar 25 – Apr 8 | May 9 – May 24 | Aug 4 – Aug 19 | matures comfortably |
| Pea | Hardy | — | Mar 11 – Mar 25 | May 5 – May 20 | Jul 25 – Aug 9 | matures comfortably |
| Spinach | Hardy | — | Mar 11 – Mar 25 | Apr 20 – Apr 30 | Aug 14 – Aug 24 | matures comfortably |
| Carrot | Half-hardy | — | Apr 1 – Apr 8 | May 31 – Jun 20 | Jul 15 – Aug 4 | matures comfortably |
| Broccoli | Half-hardy | Feb 25 – Mar 11 | Mar 25 – Apr 8 | May 19 – Jun 8 | Jul 20 – Aug 9 | matures comfortably |
Which crops fit this growing season
Using Delphi's own 179-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (Delphi)
From NOAA's 1991–2020 Climate Normals at station USC00122149. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | May 2 | May 19 | Oct 6 | Oct 21 | 156 |
| 32°F (freeze) | Apr 22 | May 6 | Oct 17 | Nov 1 | 179 |
| 28°F | Apr 8 | Apr 23 | Oct 30 | Nov 13 | 203 |
| 24°F | Mar 30 | Apr 14 | Nov 10 | Nov 28 | 228 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 74 locations is 3,223; Delphi's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 3,403 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 5,717 | cool-season crops (brassicas, greens) |
Hardiness zone 6a in Indiana
Zone 6a means an average annual extreme minimum winter temperature of about −10 to −5 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Indiana spans 4 hardiness zones in this dataset — see all Indiana locations for the full range, including zones5b, 6b, 7a.
Explore zone 6a in other states at zone 6a, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 6a mean in Indiana?
- Zone 6a means an average annual extreme minimum winter temperature of −10 to −5 °F — the standard USDA measure of which perennials survive winter. 74 locations in Indiana fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in Indiana's zone 6a is the growing season longest?
- Scotland runs the longest season on this page at about 202 days; Fort Wayne is shortest at about 159 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in Indiana's zone 6a?
- Using Delphi's frost dates (this page's median-season location): start seeds indoors about Feb 25 – Mar 11, then transplant outside about Apr 29 – May 6. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in Indiana's zone 6a have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 74 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.