Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 45681 — South Salem, OH

ZIP code 45681 (South Salem, Ross County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 20 and the first fall frost October 22.

Where ZIP 45681 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone6b−5 to 0 °F

Coldest night−20.6 to −17.8 °C

Last frostApr 20

First frostOct 22

2012 zone6a

Was 6a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for South Salem, OH…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in South Salem, OH

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 20median — 50% chance of a later frost

Safe for tender plantsMay 7only 10% chance of frost after

First fall frostOctober 22median — 10% chance by Oct 7

Growing season184 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 6 and returns around November 2.

From the NOAA station Chillicothe Mound City, OH — 14 miles away, elevation 650 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 45681

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 9 – Mar 23

SpinachSow outdoors · Mar 9 – Mar 30

Broccoli, cabbageStart indoors · Feb 9 – Feb 23

Broccoli, cabbageTransplant · Mar 30 – Apr 13

Onion setsPlant outdoors · Mar 23 – Apr 6

PotatoesPlant outdoors · Mar 30 – Apr 13

LettuceSow outdoors · Mar 23 – Apr 6

Carrots, beetsSow outdoors · Mar 30 – Apr 13

TomatoesStart indoors · Feb 23 – Mar 9

TomatoesTransplant · Apr 27 – May 11

Peppers, eggplantStart indoors · Feb 9 – Feb 23

Peppers, eggplantTransplant · May 4 – May 18

BeansSow outdoors · Apr 27 – May 11

Sweet cornSow outdoors · Apr 27 – May 11

Cucumbers, squashSow outdoors · Apr 27 – May 11

Fall lettuce, spinachSow outdoors · Aug 27 – Sep 10

GarlicPlant cloves · Oct 8 – Nov 12

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 20) and first fall frost (Oct 22) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 45681 came on Mar 10 — 13 days earlier than the 1991–2020 average (Mar 23).

average
Mar 232026
Mar 10

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 6b in Ohio

570 plants native to the lower 48 states, recorded in Ohio, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in South Salem, OH.

Soil in South Salem, OH

The soil mapped at the center of ZIP 45681 is Coolville — moderately decomposed plant material, moderately well drained.

TextureModerately decomposed plant materialtop layer

pH4.2strongly acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter60%high

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classprime farmlandUSDA classification

Map unit: Coolville silt loam, 2 to 6 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 45681; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in South Salem, OH

Summer high85 °Faverage high, July

Winter low21 °Faverage low, January

Hot days22days a year at 90 °F or more

Freezing nights114nights a year at 32 °F or less

Growing degree days3,538base 50 °F — the season’s usable heat

Longest day14 h 56 mindaylight on June 21

Shortest day9 h 24 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation43.4 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Chillicothe Mound City, OH (14 mi away); precipitation: Greenfield Wwtp, OH (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

456176b

Bourneville, OH · 6 mi

456126b

Bainbridge, OH · 7 mi

456286b

Frankfort, OH · 7 mi

451236b

Greenfield, OH · 8 mi

456246b

Cynthiana, OH · 10 mi

431156b

Clarksburg, OH · 14 mi

Ohio planting zones →

Questions about 45681

What planting zone is ZIP code 45681?

ZIP code 45681 (South Salem, OH) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in South Salem, OH?

The median last spring frost (32 °F) near 45681 is April 20; after May 7 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Chillicothe Mound City station.

When is the first frost in South Salem, OH?

The median first fall frost near 45681 is October 22, giving a median frost-free growing season of 184 days.

When should I plant tomatoes in 45681?

Start tomato seeds indoors around Feb 23 – Mar 9 and set transplants outside around Apr 27 – May 11, one to three weeks after the median last frost.

How much rain and snow does 45681 get?

About 43.4 inches of precipitation a year (NOAA 1991–2020 normals, Greenfield Wwtp station).

How hot do summers get in South Salem, OH?

The average high peaks at 85 °F in July, with about 22 days a year at 90 °F or more.

What kind of soil does 45681 have?

The USDA soil survey maps Coolville at the center of ZIP 45681: moderately decomposed plant material, moderately well drained, pH about 4.2 (strongly acidic).

Did spring come early in South Salem, OH in 2026?

Spring leaf-out near 45681 came on Mar 10 in 2026, 13 days earlier than the 1991–2020 average (Mar 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in South Salem, OH?

Intermediate onions: the longest day near 45681 is 14 h 56 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 45681 change?

Yes. The 2012 USDA map put 45681 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.