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

Planting zone for 45123 — Greenfield, OH

ZIP code 45123 (Greenfield, Highland County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 23 and the first fall frost October 21.

Where ZIP 45123 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 23

First frostOct 21

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 Greenfield, 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 Greenfield, OH

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 23median — 50% chance of a later frost

Safe for tender plantsMay 8only 10% chance of frost after

First fall frostOctober 21median — 10% chance by Oct 8

Growing season181 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 11 and returns around November 1.

From the NOAA station Washington Court House, OH — 13 miles away, elevation 958 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 45123

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 12 – Mar 26

SpinachSow outdoors · Mar 12 – Apr 2

Broccoli, cabbageStart indoors · Feb 12 – Feb 26

Broccoli, cabbageTransplant · Apr 2 – Apr 16

Onion setsPlant outdoors · Mar 26 – Apr 9

PotatoesPlant outdoors · Apr 2 – Apr 16

LettuceSow outdoors · Mar 26 – Apr 9

Carrots, beetsSow outdoors · Apr 2 – Apr 16

TomatoesStart indoors · Feb 26 – Mar 12

TomatoesTransplant · Apr 30 – May 14

Peppers, eggplantStart indoors · Feb 12 – Feb 26

Peppers, eggplantTransplant · May 7 – May 21

BeansSow outdoors · Apr 30 – May 14

Sweet cornSow outdoors · Apr 30 – May 14

Cucumbers, squashSow outdoors · Apr 30 – May 14

Fall lettuce, spinachSow outdoors · Aug 26 – Sep 9

GarlicPlant cloves · Oct 7 – Nov 11

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 23) and first fall frost (Oct 21) 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 45123 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 Greenfield, OH.

Soil in Greenfield, OH

The soil mapped at the center of ZIP 45123 is Crosby — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables

pH6.2slightly acidic; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2.5%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classNot prime farmlandUSDA classification

Map unit: Crosby-Urban land complex, 0 to 2 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 45123; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Greenfield, OH

Summer high84 °Faverage high, July

Winter low20 °Faverage low, January

Hot days12days a year at 90 °F or more

Freezing nights115nights a year at 32 °F or less

Growing degree days3,244base 50 °F — the season’s usable heat

Longest day14 h 57 mindaylight on June 21

Shortest day9 h 23 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: Washington Court House, OH (13 mi away); precipitation: Greenfield Wwtp, OH (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

456816b

South Salem, OH · 8 mi

451356b

Leesburg, OH · 8 mi

456286b

Frankfort, OH · 11 mi

451326b

Highland, OH · 11 mi

456126b

Bainbridge, OH · 11 mi

456246b

Cynthiana, OH · 12 mi

431606b

Washington Court House, OH · 13 mi

456176b

Bourneville, OH · 13 mi

Ohio planting zones →

Questions about 45123

What planting zone is ZIP code 45123?

ZIP code 45123 (Greenfield, 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 Greenfield, OH?

The median last spring frost (32 °F) near 45123 is April 23; after May 8 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Washington Court House station.

When is the first frost in Greenfield, OH?

The median first fall frost near 45123 is October 21, giving a median frost-free growing season of 181 days.

When should I plant tomatoes in 45123?

Start tomato seeds indoors around Feb 26 – Mar 12 and set transplants outside around Apr 30 – May 14, one to three weeks after the median last frost.

How much rain and snow does 45123 get?

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

How hot do summers get in Greenfield, OH?

The average high peaks at 84 °F in July, with about 12 days a year at 90 °F or more.

What kind of soil does 45123 have?

The USDA soil survey maps Crosby at the center of ZIP 45123: silt loam, somewhat poorly drained, pH about 6.2 (slightly acidic).

Did spring come early in Greenfield, OH in 2026?

Spring leaf-out near 45123 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 Greenfield, OH?

Intermediate onions: the longest day near 45123 is 14 h 57 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 45123 change?

Yes. The 2012 USDA map put 45123 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.