Flint, MI planting zone & frost dates
Flint is in USDA hardiness zone 6a. The last spring frost usually comes around May 6 and the first fall frost around October 10, for a growing season of about 155 days.
Planting calendar for Flint
Dates are counted from the average last spring frost (May 6) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Mar 11 – Mar 25 Transplant outdoors: May 13 – May 20 |
| Peppers | Start seeds indoors: Feb 25 – Mar 11 Transplant outdoors: May 20 – May 27 |
| Eggplant | Start seeds indoors: Feb 25 – Mar 11 Transplant outdoors: May 20 – May 27 |
| Broccoli | Start seeds indoors: Feb 25 – Mar 11 Transplant outdoors: Apr 8 – Apr 22 |
| Cabbage | Start seeds indoors: Feb 25 – Mar 11 Transplant outdoors: Apr 8 – Apr 22 |
| Onions (sets) | Plant outdoors: Apr 8 – Apr 22 |
| Peas | Sow outdoors: Mar 25 – Apr 8 |
| Spinach | Sow outdoors: Mar 25 – Apr 8 |
| Lettuce | Sow outdoors: Apr 8 – Apr 22 |
| Carrots | Sow outdoors: Apr 8 – Apr 22 |
| Potatoes | Plant outdoors: Apr 8 – Apr 22 |
| Beans | Sow outdoors: May 13 – May 20 |
| Sweet corn | Sow outdoors: May 13 – May 20 |
| Cucumbers | Sow outdoors: May 13 – May 20 |
| Squash & zucchini | Sow outdoors: May 13 – May 20 |
| Basil | Start seeds indoors: Mar 25 – Apr 8 Transplant outdoors: May 13 – May 20 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 15 (8 weeks before the average first fall frost on Oct 10).
Useful for zone 6a gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Cold frame / mini greenhouse — adds weeks to a short season
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 21 | May 6 | May 23 |
| First 32°F frost in fall is before | Oct 25 | Oct 10 | Sep 26 |
How to read it: in spring there is a 10% chance of a frost after May 23, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 26. A hard freeze (28°F) usually ends around April 26.
Hardiness zone by ZIP code in Flint
- 48501 zone 6a
- 48502 zone 6a
- 48503 zone 6a
- 48504 zone 6a
- 48505 zone 6a
- 48506 zone 6a
- 48507 zone 6a
- 48531 zone 6a
- 48532 zone 6a
- 48550 zone 6a
- 48551 zone 6a
- 48552 zone 6a
- 48553 zone 6a
- 48554 zone 6a
- 48555 zone 6a
- 48556 zone 6a
- 48557 zone 6a
Nearby cities
Questions
What growing zone is Flint, MI?
Flint is in USDA Plant Hardiness Zone 6a (average extreme winter low -10°F to -5°F), according to the USDA 2023 map.
When is the last frost in Flint?
The average last spring frost (32°F) in Flint is May 6. There is still a 10% chance of frost until May 23.
When can I plant tomatoes in Flint?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 13 – May 20. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Flint Bishop Intl Ap, MI (USW00014826), 7.2 km (4.5 mi) from the city center, elevation 235 m, based on 24 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.