McHenry, IL planting zone & frost dates
McHenry is in USDA hardiness zone 5b. The last spring frost usually comes around May 1 and the first fall frost around October 11, for a growing season of about 162 days.
Planting calendar for McHenry
Dates are counted from the average last spring frost (May 1) 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 6 – Mar 20 Transplant outdoors: May 8 – May 15 |
| Peppers | Start seeds indoors: Feb 20 – Mar 6 Transplant outdoors: May 15 – May 22 |
| Eggplant | Start seeds indoors: Feb 20 – Mar 6 Transplant outdoors: May 15 – May 22 |
| Broccoli | Start seeds indoors: Feb 20 – Mar 6 Transplant outdoors: Apr 3 – Apr 17 |
| Cabbage | Start seeds indoors: Feb 20 – Mar 6 Transplant outdoors: Apr 3 – Apr 17 |
| Onions (sets) | Plant outdoors: Apr 3 – Apr 17 |
| Peas | Sow outdoors: Mar 20 – Apr 3 |
| Spinach | Sow outdoors: Mar 20 – Apr 3 |
| Lettuce | Sow outdoors: Apr 3 – Apr 17 |
| Carrots | Sow outdoors: Apr 3 – Apr 17 |
| Potatoes | Plant outdoors: Apr 3 – Apr 17 |
| Beans | Sow outdoors: May 8 – May 15 |
| Sweet corn | Sow outdoors: May 8 – May 15 |
| Cucumbers | Sow outdoors: May 8 – May 15 |
| Squash & zucchini | Sow outdoors: May 8 – May 15 |
| Basil | Start seeds indoors: Mar 20 – Apr 3 Transplant outdoors: May 8 – May 15 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 16 (8 weeks before the average first fall frost on Oct 11).
Useful for zone 5b 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 16 | May 1 | May 19 |
| First 32°F frost in fall is before | Oct 24 | Oct 11 | Sep 27 |
How to read it: in spring there is a 10% chance of a frost after May 19, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 27. A hard freeze (28°F) usually ends around April 19.
Hardiness zone by ZIP code in McHenry
- 60050 zone 5b
- 60051 zone 5b
Nearby cities
- Fox Lake zone 5b, last frost Apr 24
- Crystal Lake zone 5b, last frost Apr 25
- Cary zone 5b, last frost May 1
- Wauconda zone 5b, last frost Apr 29
- Lake in the Hills zone 5b, last frost Apr 25
- Algonquin zone 5b, last frost Apr 26
- Round Lake zone 5b, last frost Apr 24
- Round Lake Beach zone 5b, last frost Apr 24
Questions
What growing zone is McHenry, IL?
McHenry is in USDA Plant Hardiness Zone 5b (average extreme winter low -15°F to -10°F), according to the USDA 2023 map.
When is the last frost in McHenry?
The average last spring frost (32°F) in McHenry is May 1. There is still a 10% chance of frost until May 19.
When can I plant tomatoes in McHenry?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 8 – May 15. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Mc Henry -Wg Stratton L&D, IL (USC00115493), 2.9 km (1.8 mi) from the city center, elevation 224 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.