River Grove, IL planting zone & frost dates
River Grove is in USDA hardiness zone 6a. The last spring frost usually comes around April 16 and the first fall frost around October 28, for a growing season of about 193 days.
Planting calendar for River Grove
Dates are counted from the average last spring frost (April 16) 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 19 – Mar 5 Transplant outdoors: Apr 23 – Apr 30 |
| Peppers | Start seeds indoors: Feb 5 – Feb 19 Transplant outdoors: Apr 30 – May 7 |
| Eggplant | Start seeds indoors: Feb 5 – Feb 19 Transplant outdoors: Apr 30 – May 7 |
| Broccoli | Start seeds indoors: Feb 5 – Feb 19 Transplant outdoors: Mar 19 – Apr 2 |
| Cabbage | Start seeds indoors: Feb 5 – Feb 19 Transplant outdoors: Mar 19 – Apr 2 |
| Onions (sets) | Plant outdoors: Mar 19 – Apr 2 |
| Peas | Sow outdoors: Mar 5 – Mar 19 |
| Spinach | Sow outdoors: Mar 5 – Mar 19 |
| Lettuce | Sow outdoors: Mar 19 – Apr 2 |
| Carrots | Sow outdoors: Mar 19 – Apr 2 |
| Potatoes | Plant outdoors: Mar 19 – Apr 2 |
| Beans | Sow outdoors: Apr 23 – Apr 30 |
| Sweet corn | Sow outdoors: Apr 23 – Apr 30 |
| Cucumbers | Sow outdoors: Apr 23 – Apr 30 |
| Squash & zucchini | Sow outdoors: Apr 23 – Apr 30 |
| Basil | Start seeds indoors: Mar 5 – Mar 19 Transplant outdoors: Apr 23 – Apr 30 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 2 (8 weeks before the average first fall frost on Oct 28).
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 3 | Apr 16 | May 1 |
| First 32°F frost in fall is before | Nov 11 | Oct 28 | Oct 15 |
How to read it: in spring there is a 10% chance of a frost after May 1, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 15. A hard freeze (28°F) usually ends around April 5.
Hardiness zone by ZIP code in River Grove
- 60171 zone 6a
Nearby cities
- Elmwood Park zone 6a, last frost Apr 16
- Franklin Park zone 6a, last frost Apr 16
- Melrose Park zone 6a, last frost Apr 16
- River Forest zone 6a, last frost Apr 11
- Norridge zone 6a, last frost Apr 16
- Schiller Park zone 6a, last frost Apr 16
- Maywood zone 6a, last frost Apr 11
- Forest Park zone 6a, last frost Apr 11
Questions
What growing zone is River Grove, IL?
River Grove 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 River Grove?
The average last spring frost (32°F) in River Grove is April 16. There is still a 10% chance of frost until May 1.
When can I plant tomatoes in River Grove?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 23 – Apr 30. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Chicago Ohare Intl Ap, IL (USW00094846), 11.2 km (7.0 mi) from the city center, elevation 201 m, based on 28 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.