What Grows in Union, Ohio

USDA Zones 6a-7b · 5K acres

Union, Ohio, sits in USDA hardiness zones 6a-7b — a zone band wide enough that plant choice, not possibility, is the interesting question.

Growers here do well with tomato, sweet corn, apple, and pawpaw — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.

Score your parcel · free

Even in Union, no two yards are alike.

A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Union lot. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

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Quick Facts

USDA Zones

6a-7b

Last Hard Freeze (28°F)

Mar 18

Town normal — light frosts run a few weeks later

First Hard Freeze (28°F)

Nov 22

Town normal — light frosts arrive a few weeks earlier

City Area

5K acres

Hardiness Zone Range

6a
7b
3a (Cold)13b (Hot)

Zone maps are averages across Union. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.

Soil varies lot by lot — soil types explained.

Is it too late to plant in Union?

For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Feb 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 18 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 22 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.

Growing Challenges in Ohio

What an experienced grower plans around here — each one has a move.

Heavy clay soils across much of northern Ohio require amendment for drainage

A raised bed fixes the drainage in one weekend — and amended clay repays the effort as some of the richest soil there is.

Variable spring weather with late frost risk through mid-May

Watch your local last-frost normal, not the region's — holding tender plants two extra weeks beats replanting a bed.

Japanese beetles and tomato hornworms are common garden pests

Hand-pick early, row-cover young plants, and skip broad sprays — extension IPM guides keep the beneficial insects on your side.

Wet springs can delay planting and promote root rot

Raised or mounded rows shed spring water and warm earlier — where puddles linger, drainage is the first project worth doing.

For cultivar selection, pest pressure, and planting-time guidance specific to Ohio, the Ohio State University Extension is the authoritative local source.

Environmental Intelligence

Understanding what's nearby helps you make informed decisions about where and how to grow.

Total Sites

969

within ~10 miles of Union

Risk Level

High

Highest-severity

11 Superfund sites

Severity Distribution

within ~10 miles of Union

High15Moderate301Low653

Highest-Severity Sites

Brookville Municipality Pws
PFAS Sampling · PFAS Detected
Buckeye Quality Cleaners
Superfund · Superfund (Non-NPL)
Grandview Medical Center Pws
PFAS Sampling · PFAS Detected
Kenbrook Medical Center Mercury Spill
Superfund · Superfund (Non-NPL)
Needmore Road VOC Plume
Superfund · Superfund (Non-NPL)

A note from Gnorman

What an experienced grower watches for around here

In and around Union, Toxic Release Inventory runs higher than the national average — 71 sites nearby. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.

Toxic Release Inventory: TRI facilities report annual chemical releases to air, water, and land.

Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.

Free Report

Check your specific parcel in Union

Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.

Three things about your exact spot that zone averages miss:

Your soil pHYour frost-free daysYour sun & shade

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources analyzed in seconds

Your Specific Parcel Matters

Union Average

  • USDA Zones 6a-7b
  • Generic soil type for the area
  • State-average frost dates

YOUR Parcel

  • Your exact hardiness zone
  • Your SSURGO soil type & pH
  • Your sun exposure, cast in 3D

See MY Growing Report

Free Report

Read your specific parcel in Union

Pull a site-specific report for your exact address in Union, Ohio — soil, sun, drainage, frost risk, and scored plant recommendations.

Three things about your exact spot that zone averages miss:

Your soil pHYour frost-free daysYour sun & shade

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources analyzed in seconds

Key Growing Facts for Union, Ohio

  • USDA Hardiness Zones: 6a-7b (USDA PHZM 2023)
  • Last Hard Freeze (28°F): Mar 18 (town normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
  • First Hard Freeze (28°F): Nov 22 (town normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
  • Days Between Hard Freezes: ~249 (town normal, NOAA 1991–2020 Climate Normals)
  • Land Area: 5K acres (US Census TIGER 2025)

Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. Boundaries: US Census TIGER/Line 2025.

Frequently Asked Questions

What hardiness zone is Union, Ohio?

Union sits in USDA hardiness zones 6a-7b, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.

Is it too late to plant in Union?

For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Feb 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 18 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 22 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.

When does frost risk typically end in Union?

The last hard freeze (28°F) in Union typically lands around Mar 18, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.

When is the first frost in Union?

The first hard freeze (28°F) in Union typically arrives around Nov 22, per NOAA 1991–2020 climate normals — the point most tender summer crops finish. Lighter frosts usually reach a couple of weeks earlier, so watch the forecast from late summer on and harvest or cover tender plants before the first cold night.

What vegetables grow in Union?

Union's zones 6a-7b support a wide range — strong performers include Tomato, Sweet Corn, Apple, Pawpaw, and Buckeye. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.

Which hardiness zone is Union, really?

Officially, Union sits in USDA zones 6a-7b (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,112 plants against what's actually there.

Is the soil safe to grow vegetables in Union?

The federal record around Union runs heavier than most — 969 documented sites — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.

How do I protect my plants from frost in Union?

As the season closes around the first 28°F hard freeze near Nov 22 (NOAA 1991–2020 climate normals), a few moves buy time: cover tender plants with floating row cover or an old sheet on still, clear nights, water the soil the afternoon before a freeze so it holds warmth overnight, and harvest frost-tender crops like tomatoes, peppers, and basil before the first hard night. Hardy greens and root crops shrug off light frost and often sweeten after it, so leave them in.

Everything on this page is a Union average. Your yard writes its own version — we read soil, sun, drainage, and frost at your exact address. Try it for 14 days — no card required.