Mount Vernon, OH planting zone & frost dates

Mount Vernon is in USDA hardiness zone 6a. The last spring frost usually comes around May 1 and the first fall frost around October 10, for a growing season of about 161 days.

USDA hardiness zone6aavg. extreme winter low -10°F to -5°F
Average last spring frostMay 190% chance of no frost after May 18
Average first fall frostOctober 1010% chance of frost by September 27
Growing season161 daysfrost-free days in an average year

Planting calendar for Mount Vernon

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.

CropWhen
TomatoesStart seeds indoors: Mar 6 – Mar 20
Transplant outdoors: May 8 – May 15
PeppersStart seeds indoors: Feb 20 – Mar 6
Transplant outdoors: May 15 – May 22
EggplantStart seeds indoors: Feb 20 – Mar 6
Transplant outdoors: May 15 – May 22
BroccoliStart seeds indoors: Feb 20 – Mar 6
Transplant outdoors: Apr 3 – Apr 17
CabbageStart seeds indoors: Feb 20 – Mar 6
Transplant outdoors: Apr 3 – Apr 17
Onions (sets)Plant outdoors: Apr 3 – Apr 17
PeasSow outdoors: Mar 20 – Apr 3
SpinachSow outdoors: Mar 20 – Apr 3
LettuceSow outdoors: Apr 3 – Apr 17
CarrotsSow outdoors: Apr 3 – Apr 17
PotatoesPlant outdoors: Apr 3 – Apr 17
BeansSow outdoors: May 8 – May 15
Sweet cornSow outdoors: May 8 – May 15
CucumbersSow outdoors: May 8 – May 15
Squash & zucchiniSow outdoors: May 8 – May 15
BasilStart 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 15 (8 weeks before the average first fall frost on Oct 10).

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 18May 1May 18
First 32°F frost in fall is beforeOct 24Oct 10Sep 27

How to read it: in spring there is a 10% chance of a frost after May 18, 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 21.

Hardiness zone by ZIP code in Mount Vernon

Nearby cities

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

Questions

What growing zone is Mount Vernon, OH?

Mount Vernon 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 Mount Vernon?

The average last spring frost (32°F) in Mount Vernon is May 1. There is still a 10% chance of frost until May 18.

When can I plant tomatoes in Mount Vernon?

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 Fredericktown 4 S, OH (USC00332956), 4.8 km (3.0 mi) from the city center, elevation 320 m, based on 17 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.