Macomb, IL planting zone & frost dates
Macomb is in USDA hardiness zone 6a. The last spring frost usually comes around April 17 and the first fall frost around October 22, for a growing season of about 185 days.
Planting calendar for Macomb
Dates are counted from the average last spring frost (April 17) 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: Feb 20 – Mar 6 Transplant outdoors: Apr 24 – May 1 |
| Peppers | Start seeds indoors: Feb 6 – Feb 20 Transplant outdoors: May 1 – May 8 |
| Eggplant | Start seeds indoors: Feb 6 – Feb 20 Transplant outdoors: May 1 – May 8 |
| Broccoli | Start seeds indoors: Feb 6 – Feb 20 Transplant outdoors: Mar 20 – Apr 3 |
| Cabbage | Start seeds indoors: Feb 6 – Feb 20 Transplant outdoors: Mar 20 – Apr 3 |
| Onions (sets) | Plant outdoors: Mar 20 – Apr 3 |
| Peas | Sow outdoors: Mar 6 – Mar 20 |
| Spinach | Sow outdoors: Mar 6 – Mar 20 |
| Lettuce | Sow outdoors: Mar 20 – Apr 3 |
| Carrots | Sow outdoors: Mar 20 – Apr 3 |
| Potatoes | Plant outdoors: Mar 20 – Apr 3 |
| Beans | Sow outdoors: Apr 24 – May 1 |
| Sweet corn | Sow outdoors: Apr 24 – May 1 |
| Cucumbers | Sow outdoors: Apr 24 – May 1 |
| Squash & zucchini | Sow outdoors: Apr 24 – May 1 |
| Basil | Start seeds indoors: Mar 6 – Mar 20 Transplant outdoors: Apr 24 – May 1 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 27 (8 weeks before the average first fall frost on Oct 22).
Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 4 | Apr 17 | May 2 |
| First 32°F frost in fall is before | Nov 1 | Oct 22 | Oct 7 |
How to read it: in spring there is a 10% chance of a frost after May 2, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 7. A hard freeze (28°F) usually ends around April 7.
Hardiness zone by ZIP code in Macomb
- 61455 zone 6a
Nearby cities
- Galesburg zone 5b, last frost Apr 20
- Canton zone 6a, last frost Apr 17
- Jacksonville zone 6a, last frost Apr 17
- Quincy zone 6a, last frost Apr 8
- Pekin zone 6a, last frost Apr 16
- Rock Island zone 5b, last frost Apr 19
- Moline zone 5b, last frost Apr 19
- East Moline zone 5b, last frost Apr 24
Questions
What growing zone is Macomb, IL?
Macomb 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 Macomb?
The average last spring frost (32°F) in Macomb is April 17. There is still a 10% chance of frost until May 2.
When can I plant tomatoes in Macomb?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 24 – May 1. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Prairie City 2S, IL (USC00116970), 22.9 km (14.2 mi) from the city center, elevation 198 m, based on 16 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.