Unionville, Pennsylvania, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, cabbage, hazelnut, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Unionville, 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 Unionville lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Unionville — soil, climate, flood, and parcel records. How we handle your address.
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Unionville — the short answer
Unionville, Pennsylvania: USDA zone 6a, about 184 days between hard freezes, across 2K acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 25
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~184
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 2K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 6a is Unionville's average, not your lot's — a low corner or a tree line moves it. Against Unionville's 184-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Unionville
Each reading below is measured for Unionville itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredUnionville runs about 184 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredUnionville sits in USDA hardiness zone 6a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Unionville is in
Unionville sits in the Western Allegheny Plateau — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Unionville's own centroid rather than borrowed from Butler County.
What Grows in Unionville
Every plant below cleared Unionville's own zone 6a and its 184-day season. Each card opens that plant's Pennsylvania profile. How we score.
Is it too late to plant in Unionville?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 28; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 25 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 26 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
Documented around Unionville
Spotted lanternfly documented 3 miles from Unionville, first recorded 2022. What to watch for.
What's on the federal record near Unionville
Closest first, within ~10 miles of Unionville. Listing isn't leaking, and distance isn't exposure.
- UNIONVILLE VOL FIRE COUnderground Storage Tanks · 1300 ft
- BUTLER SHOPUnderground Storage Tanks · 0.8 mi
- STOUGHTON ACRES GCUnderground Storage Tanks · 1.4 mi
- PIONEER SALES & SVCUnderground Storage Tanks · 1.7 mi
- LAKE ARTHUR CCUnderground Storage Tanks · 1.8 mi
- BUTLER REPORTING CTRUnderground Storage Tanks · 1.8 mi
- CENTER TWP MUNI BLDGUnderground Storage Tanks · 1.8 mi
- KWIK FILL S 13Underground Storage Tanks · 2.8 mi
- KWIK FILL S0013 278Brownfields · 2.8 mi
- JIFFY MINI MART 3Underground Storage Tanks · 3.2 mi
- FRANKLIN TOWNSHIP MUNICIPAL BUILDINGBrownfields · 3.4 mi
- FRANKLIN TWP PROSPECTUnderground Storage Tanks · 3.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Unionville's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Unionville.
Total Sites
369
within ~10 miles of Unionville
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Unionville
Severity Distribution
within ~10 miles of Unionville
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •TRI facilities report what they release. Check the wind — downwind beds catch more of it.
Check your specific parcel in Unionville
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Unionville average
Your land is one point inside Unionville
Everything above resolves to Unionville as a whole — one PHZM band and one 28°F frost record, read across 2K acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at town scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the Unionville Average
Unionville Average
- ●USDA Zones 6a, averaged across Unionville
- ●One soil character for all of Unionville
- ●Frost dates read at Unionville's scale: Apr 25 to Oct 26
YOUR Parcel
- ✓Your exact zone, not Unionville's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Unionville
Pull a site-specific report for your exact address in Unionville, Pennsylvania — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Unionville averages can't show:
We read public map data around Unionville — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Unionville average
How we know this about Unionville
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Unionville’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Unionville
When does frost risk typically end in Unionville?
The last hard freeze (28°F) in Unionville typically lands around Apr 25, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about May 16.
When is the first frost in Unionville?
The first hard freeze (28°F) in Unionville typically arrives around Oct 26, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 12, so the watching starts about Sep 26 — about 184 days after the spring freeze cleared.
How long is the growing season in Unionville?
Measured between 28°F hard freezes, Unionville sees about 184 frost-free days — roughly Apr 25 through Oct 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 16 to Oct 12, about 149 days.
Is the soil safe to grow vegetables in Unionville?
The federal record around Unionville is a meaningful one — 369 documented sites, mostly Underground Storage Tanks entries (209), the nearest Underground Storage Tanks record about 0.2 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in Unionville?
From about Sep 26 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 26 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 26. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Unionville's scale — its 6a band and its 184-day season. Your yard writes its own version of Unionville's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Unionville’s own scale
7 of the readings below were taken at Unionville's own scale — its own ~184-day season between 28°F freezes, the 1,644 acres it covers and 369 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Unionville's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Unionville's own 28°F hard-freeze dates, about Apr 25 and Oct 26 and the ~184-day span between themNOAA 1991–2020 Climate Normals
- 369 documented contamination sites on the federal record near Unionville, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Unionville's boundary and the 1,644 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~184-day seasonGrowable Ground crop-matching engine
- The ecoregion at Unionville's own centroid, the Western Allegheny PlateauUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Unionvillelydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Unionville's 1,644 acres read through its county's SSURGO summaryfrom Butler County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Butler County
- The growing challenges every Pennsylvania grower plans around — written at state scale, so they stay on the state guidefrom Pennsylvania
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Butler County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Unionville's 1,644 acreswhy one lot differs from the next →
- Which side of Unionville you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,644 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Unionville-wide figureread your own land →
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