Indianapolis, Indiana: planting zone & frost dates
Indianapolis is in USDA plant hardiness zone 6b, where the average coldest winter night reaches -5 to 0°F (-20.6 to -17.8°C). The typical last spring frost is around Apr 26 and the first fall frost around Oct 16.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 5 | Oct 7 |
| Typical planning date (30% risk) | Apr 26 | Oct 16 |
| Median (50%) | Apr 20 | Oct 21 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station INDIANAPOLIS SE SIDE, IN (USC00124272), 5.9 mi (9.5 km) from the city center and 128 ft higher than the city center (+39 m). Record used for the 1991–2020 normals: 23 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Indianapolis
Indianapolis spans more than one half-zone. Share of the city's land area by zone (via its 35 ZIP codes): 6b (53%), 6a (47%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
ZIP codes in Indianapolis and their zones
| ZIP | Zone | Share of city land |
|---|---|---|
| 46239 | 6a | 7.8% |
| 46241 | 6b | 6.6% |
| 46217 | 6b | 5.9% |
| 46221 | 6b | 5.5% |
| 46227 | 6b | 4.4% |
| 46259 | 6a | 4.3% |
| 46237 | 6a | 4.0% |
| 46203 | 6b | 3.6% |
| 46219 | 6a | 3.5% |
| 46254 | 6b | 3.5% |
| 46278 | 6a | 3.5% |
| 46268 | 6a | 3.4% |
| 46220 | 6b | 3.2% |
| 46226 | 6a | 2.9% |
| 46256 | 6a | 2.8% |
| 46222 | 6b | 2.7% |
| 46218 | 6a | 2.6% |
| 46229 | 6a | 2.6% |
| 46260 | 6a | 2.6% |
| 46240 | 6b | 2.4% |
| 46214 | 6b | 2.1% |
| 46250 | 6a | 2.1% |
| 46228 | 6b | 2.0% |
| 46208 | 6b | 1.8% |
| 46205 | 6b | 1.7% |
| 46113 | 6a | 1.6% |
| 46201 | 6b | 1.5% |
| 46202 | 6b | 1.5% |
| 46231 | 6b | 1.5% |
| 46234 | 6a | 1.5% |
| 46235 | 6a | 1.5% |
| 46225 | 6b | 1.1% |
| 46224 | 6b | 1.0% |
| 46204 | 6b | 0.3% |
| 46206 | 6b | 0.0% |
Vegetable planting calendar for Indianapolis
Dates are counted from the 30%-risk frost dates above (last frost Apr 26, first frost Oct 16). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Mar 1 – Mar 15 | May 3 – May 17 | — | — |
| Pepper | Feb 15 – Mar 1 | May 10 – May 24 | — | — |
| Lettuce | Mar 15 – Mar 29 | Apr 12 – May 3 | Mar 29 – May 10 | Aug 7 – Sep 4 |
| Green Beans | — | — | May 3 – Jun 7 | Jul 24 – Aug 7 |
| Sweet Corn | — | — | May 3 – May 31 | — |
| Zucchini & Summer Squash | Mar 29 – Apr 5 | May 3 – May 17 | May 3 – May 24 | Jul 24 – Aug 7 |
| Cucumber | Mar 29 – Apr 5 | May 10 – May 17 | May 3 – May 24 | Jul 24 – Aug 7 |
| Carrot | — | — | Apr 5 – May 10 | Jul 24 – Aug 7 |
| Onion | Feb 1 – Feb 15 | Mar 29 – Apr 12 | — | — |
| Potato | — | Mar 29 – Apr 19 | — | — |
| Basil | Mar 15 – Mar 29 | May 10 – May 24 | May 10 – May 31 | — |
| Spinach | — | — | Mar 15 – Apr 12 | Aug 21 – Sep 18 |
| Kale | Mar 1 – Mar 15 | Mar 29 – Apr 19 | Mar 29 – Apr 19 | Aug 7 – Sep 4 |
| Broccoli | Mar 1 – Mar 15 | Apr 12 – May 3 | — | Jul 24 – Aug 7 |
| Peas | — | — | Mar 15 – Apr 5 | Aug 7 – Aug 21 |
| Eggplant | Feb 15 – Mar 1 | May 10 – May 24 | — | — |
| Cabbage | Mar 1 – Mar 15 | Mar 29 – Apr 12 | — | Jul 24 – Aug 7 |
| Radish | — | — | Mar 22 – May 10 | Sep 4 – Oct 2 |
| Strawberry | — | Mar 29 – Apr 19 | — | — |
| Beets | — | — | Apr 5 – May 17 | Aug 7 – Aug 21 |
Nearby cities in Indiana
- Carmel — zone 6a, last frost Apr 28, first frost Oct 15
- Fishers — zone 6a, last frost Apr 28, first frost Oct 15
- Bloomington — zone 6b, last frost Apr 22, first frost Oct 21
- Fort Wayne — zone 6a, last frost May 1, first frost Oct 16
- South Bend — zone 6a, last frost May 7, first frost Oct 14
- Evansville — zone 7a, last frost Apr 2, first frost Nov 4
More: all Indiana cities · other zone 6b cities: Columbus, OH, Boston, MA, Detroit, MI, Kansas City, MO, Cincinnati, OH, Pittsburgh, PA, Buffalo, NY, Toledo, OH
Indianapolis gardening questions
When is the last frost in Indianapolis, IN?
Plan around Apr 26. At NOAA's Indianapolis SE Side, IN station, 5.9 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 20, and after May 5 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 7. The 90% and 10% dates are 29 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Indianapolis, IN?
Start seeds indoors Mar 1 – Mar 15 and set transplants outside May 3 – May 17, once nights stay above 50°F and the soil is near 60°F. That leaves 173 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Indianapolis?
About 183 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 163 days, and in 1 year in 10 it runs 203 days or more. In fall there is a 10% chance of frost by Oct 7 and a 30% chance by Oct 16. That ranks 3rd longest of 8 Indiana cities on this site.
When should I plant a fall garden in Indianapolis?
Count back from the first fall frost (Oct 16): transplant broccoli Jul 24 – Aug 7; sow kale Aug 7 – Sep 4; sow lettuce Aug 7 – Sep 4; sow radishes Sep 4 – Oct 2. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 1. How the math works: succession and fall planting.
Did Indianapolis's hardiness zone change on the 2023 map?
Yes. Most of Indianapolis was zone 6a on the 2012 map and is zone 6b on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
Is all of Indianapolis in zone 6b?
No. Zone 6b covers about 53% of the city's land; the rest is in 6a (47%), measured across the city's 35 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.