Morton, IL planting zone & frost dates

Morton is in USDA hardiness zone 6a. The last spring frost usually comes around April 21 and the first fall frost around October 17, for a growing season of about 178 days.

USDA hardiness zone6aavg. extreme winter low -10°F to -5°F
Average last spring frostApril 2190% chance of no frost after May 7
Average first fall frostOctober 1710% chance of frost by October 3
Growing season178 daysfrost-free days in an average year

Planting calendar for Morton

Dates are counted from the average last spring frost (April 21) 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.

CropWhen
TomatoesStart seeds indoors: Feb 24 – Mar 10
Transplant outdoors: Apr 28 – May 5
PeppersStart seeds indoors: Feb 10 – Feb 24
Transplant outdoors: May 5 – May 12
EggplantStart seeds indoors: Feb 10 – Feb 24
Transplant outdoors: May 5 – May 12
BroccoliStart seeds indoors: Feb 10 – Feb 24
Transplant outdoors: Mar 24 – Apr 7
CabbageStart seeds indoors: Feb 10 – Feb 24
Transplant outdoors: Mar 24 – Apr 7
Onions (sets)Plant outdoors: Mar 24 – Apr 7
PeasSow outdoors: Mar 10 – Mar 24
SpinachSow outdoors: Mar 10 – Mar 24
LettuceSow outdoors: Mar 24 – Apr 7
CarrotsSow outdoors: Mar 24 – Apr 7
PotatoesPlant outdoors: Mar 24 – Apr 7
BeansSow outdoors: Apr 28 – May 5
Sweet cornSow outdoors: Apr 28 – May 5
CucumbersSow outdoors: Apr 28 – May 5
Squash & zucchiniSow outdoors: Apr 28 – May 5
BasilStart seeds indoors: Mar 10 – Mar 24
Transplant outdoors: Apr 28 – May 5

Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 22 (8 weeks before the average first fall frost on Oct 17).

Useful for zone 6a gardens

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Frost risk in detail

90% chance50% chance10% chance
Last 32°F frost in spring is afterApr 7Apr 21May 7
First 32°F frost in fall is beforeOct 30Oct 17Oct 3

How to read it: in spring there is a 10% chance of a frost after May 7, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 3. A hard freeze (28°F) usually ends around April 9.

Hardiness zone by ZIP code in Morton

Nearby cities

All cities in Illinois → · Other zone 6a cities →

Questions

What growing zone is Morton, IL?

Morton 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 Morton?

The average last spring frost (32°F) in Morton is April 21. There is still a 10% chance of frost until May 7.

When can I plant tomatoes in Morton?

Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 28 – May 5. Start seeds indoors 6–8 weeks before the last frost.

Frost dates: NOAA U.S. Climate Normals 1991–2020, station Congerville 2Nw, IL (USC00111836), 18.4 km (11.4 mi) from the city center, elevation 195 m, based on 20 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.