South Holland, IL planting zone & frost dates
South Holland is in USDA hardiness zone 6a. The last spring frost usually comes around April 23 and the first fall frost around October 20, for a growing season of about 179 days.
Planting calendar for South Holland
Dates are counted from the average last spring frost (April 23) 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 26 – Mar 12 Transplant outdoors: Apr 30 – May 7 |
| Peppers | Start seeds indoors: Feb 12 – Feb 26 Transplant outdoors: May 7 – May 14 |
| Eggplant | Start seeds indoors: Feb 12 – Feb 26 Transplant outdoors: May 7 – May 14 |
| Broccoli | Start seeds indoors: Feb 12 – Feb 26 Transplant outdoors: Mar 26 – Apr 9 |
| Cabbage | Start seeds indoors: Feb 12 – Feb 26 Transplant outdoors: Mar 26 – Apr 9 |
| Onions (sets) | Plant outdoors: Mar 26 – Apr 9 |
| Peas | Sow outdoors: Mar 12 – Mar 26 |
| Spinach | Sow outdoors: Mar 12 – Mar 26 |
| Lettuce | Sow outdoors: Mar 26 – Apr 9 |
| Carrots | Sow outdoors: Mar 26 – Apr 9 |
| Potatoes | Plant outdoors: Mar 26 – Apr 9 |
| Beans | Sow outdoors: Apr 30 – May 7 |
| Sweet corn | Sow outdoors: Apr 30 – May 7 |
| Cucumbers | Sow outdoors: Apr 30 – May 7 |
| Squash & zucchini | Sow outdoors: Apr 30 – May 7 |
| Basil | Start seeds indoors: Mar 12 – Mar 26 Transplant outdoors: Apr 30 – May 7 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 25 (8 weeks before the average first fall frost on Oct 20).
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 9 | Apr 23 | May 11 |
| First 32°F frost in fall is before | Nov 1 | Oct 20 | Oct 6 |
How to read it: in spring there is a 10% chance of a frost after May 11, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 6. A hard freeze (28°F) usually ends around April 12.
Hardiness zone by ZIP code in South Holland
- 60473 zone 6a
Nearby cities
- Dolton zone 6a, last frost Apr 23
- Harvey zone 6a, last frost Apr 23
- Riverdale zone 6a, last frost Apr 23
- Homewood zone 6a, last frost Apr 23
- Lansing zone 6a, last frost Apr 23
- Calumet City zone 6a, last frost Apr 23
- Markham zone 6a, last frost Apr 23
- Hazel Crest zone 6a, last frost Apr 23
Questions
What growing zone is South Holland, IL?
South Holland 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 South Holland?
The average last spring frost (32°F) in South Holland is April 23. There is still a 10% chance of frost until May 11.
When can I plant tomatoes in South Holland?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 30 – May 7. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Park Forest, IL (USC00116616), 13.3 km (8.3 mi) from the city center, elevation 216 m, based on 26 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.