USDA hardiness zone lookup
Indianapolis, IN — USDA Zone 6a
Indianapolis, Indiana · 179-day growing season
Frost dates and growing season in Indianapolis
| USDA hardiness zone | Zone 6a |
|---|---|
| Average last spring frost | April 22 |
| Average first fall frost | October 18 |
| Growing season length | ~179 days |
| Temperature range (F) | -10 to 0°F |
| Temperature range (C) | -23 to -18°C |
All of Indianapolis's mapped ZIP codes fall in the same hardiness band, Zone 6a.
These are 50%-probability averages modeled from Indianapolis's USDA hardiness zone and regional climate normals — not a single-station reading. In a typical year the last spring frost will have passed by April 22, but a colder-than-average year can run 1-2 weeks later. Plant tender crops (tomatoes, peppers, basil) once both soil and night temperatures are consistently warm — a thermometer beats the calendar.
Growing season in Indianapolis
Indianapolis, Indiana sits in USDA Zone 6a, with roughly 179 frost-free days between an average last spring frost around April 22 and a first fall frost around October 18. That is a standard temperate season — most common vegetables finish comfortably, and a single main planting plus one succession round works well. Indianapolis lies near 39.8°N; higher-latitude gardens get longer midsummer days but a tighter shoulder season at this zone. As a large metro, the built-up core typically runs up to half a zone warmer than outlying suburbs through the urban heat-island effect — sheltered city gardens often push tender crops a little earlier than the average suggests.
What grows in Indianapolis
Indianapolis falls in USDA Zone 6a, so the same hardiness constraints apply as the full Zone 6 guide. Vegetables, herbs, and fruit trees rated to Zone 6a (or hardier) will overwinter here in a typical year.
- Tomatoes (all types)
- Peppers, eggplant
- Squash, melons, cucumbers
- Beans, peas
- Sweet corn
- Apples, pears, peaches, plums
- Cherries, blueberries
- Asparagus, rhubarb
- Garlic (fall-planted)
- Strawberries
What to plant in Indianapolis this week
Indianapolis is in high summer — most spring plantings are in. Keep an eye on watering and start planning your fall crop. Cool-season seedlings (broccoli, cabbage, lettuce) can be started indoors for a fall transplant.
- When to plant tomatoes in zone 6
- When to plant peppers in zone 6
- When to plant bush beans in zone 6
- When to plant cucumbers in zone 6
- When to plant basil in zone 6
Full planting calendar for Indianapolis
Crop-by-crop sowing, transplant, and harvest dates calibrated to zone 6 averages:
- When to plant tomatoes in zone 6
- When to plant peppers in zone 6
- When to plant basil in zone 6
- When to plant garlic in zone 6
- When to plant lettuce in zone 6
- When to plant bush beans in zone 6
- When to plant cucumbers in zone 6
- When to plant summer squash in zone 6
- When to plant peas in zone 6
- When to plant carrots in zone 6
ZIP codes in Indianapolis
Drill down to the precise frost window and planting calendar for a specific ZIP in Indianapolis:
- 46204 — Indianapolis (Zone 6a)
- 46202 — Indianapolis (Downtown) (Zone 6b)
- 46219 — Indianapolis (Irvington) (Zone 6a)
- 46226 — Indianapolis (Northeast) (Zone 6a)
Local microclimate notes
Zone tables give you the average — but Indianapolisgardens vary. South-facing walls and paved areas can run a full half-zone warmer than the published rating. Low-lying spots, frost pockets, and shaded north sides can run colder. If you've gardened here a few seasons, your own frost record — the last time you actually got frost damage — beats any national average.
Source and methodology
Hardiness zone from the USDA Plant Hardiness Zone Map (2023 revision). Frost-date and growing-season figures are modeled from Indianapolis's USDA hardiness zone and regional NOAA 1991-2020 climate normals — zone-level estimates, not a per-station record, so treat them as planning guidance and confirm against your own local frost history. Crop recommendations draw on US Cooperative Extension references, curated by the Growli editorial team. Last reviewed June 2026.
Other cities in Indiana
- Bloomington, IN — USDA Zone 6b
- Carmel, IN — USDA Zone 6a
- Evansville, IN — USDA Zone 7a
- Fort Wayne, IN — USDA Zone 6a
- Merrillville, IN — USDA Zone 6a
- Mishawaka, IN — USDA Zone 6a
- Noblesville, IN — USDA Zone 6a
- Portage, IN — USDA Zone 6a
- South Bend, IN — USDA Zone 6a
- Valparaiso, IN — USDA Zone 6a
- West Lafayette, IN — USDA Zone 6a
- All of Indiana by zone