Unionville, Pennsylvania, sits in USDA hardiness zone 6b — 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 1,085 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.
No card required · your parcel report in seconds — read in full free for your first 14 days
Unionville — the short answer
Unionville, Pennsylvania: USDA zone 6b, about 203 days between hard freezes, across 156 acres of town.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 11
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 31
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~203
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 156 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 6b is Unionville's average, not your lot's — a low corner or a tree line moves it. Against Unionville's 203-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 203 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredUnionville sits in USDA hardiness zone 6b.
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 Ridge and Valley — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Unionville's own centroid rather than borrowed from Centre County.
What Grows in Unionville
Every plant below cleared Unionville's own zone 6b and its 203-day season. Each card opens that plant's Pennsylvania profile. How we score.
More to grow in Pennsylvania
Pennsylvania has a growing page for many more plants than fit above — a rotating sample of the rest of the shelf.
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 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 11 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 31 — 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.
Documented around Unionville
Spotted lanternfly documented 0 miles from Unionville, first recorded 2020. 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.
- CE 334Nitrate · 1.6 mi
- UNIONVILLEUnderground Storage Tanks · 1.7 mi
- CON LIME INC/BELLEFONTEToxics Release Inventory · 2.2 mi
- CON LIME INC/BELLEFONTEBrownfields · 2.2 mi
- WELLARS MOBILUnderground Storage Tanks · 2.5 mi
- HOWARD GROVE PRINTINGBrownfields · 2.6 mi
- CE 421Nitrate · 3.0 mi
- CE 258Nitrate · 3.2 mi
- CE 683Nitrate · 3.4 mi
- BELLEFONTE AIRPORTUnderground Storage Tanks · 3.5 mi
- FILLMORE GEN STOREUnderground Storage Tanks · 3.5 mi
- PENN STATE ARL PTI TEST TRACKBrownfields · 3.6 mi
6 more sites are on the record inside the same radius.
Measured from Unionville's center, not your beds. Run your own address for what's upwind of you specifically.
Browse the full contamination data for this area
Environmental Intelligence
The counts behind that headline — every source type on the record near Unionville.
Total Sites
484
within ~10 miles of Unionville
Risk Level
Elevated
Highest-severity
2 Superfund sites
Sources Checked
within ~10 miles of Unionville
Severity Distribution
within ~10 miles of Unionville
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Unionville, PFAS runs higher than the national average — 6 sites within ~10 miles of Unionville. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Unionville
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,085 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 156 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 6b, averaged across Unionville
- ●One soil character for all of Unionville
- ●Frost dates read at Unionville's scale: Apr 11 to Oct 31
YOUR Parcel
- ✓Your exact zone, not Unionville's 6b
- ✓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 11, 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 2.
When is the first frost in Unionville?
The first hard freeze (28°F) in Unionville typically arrives around Oct 31, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 17, so the watching starts about Oct 1 — about 203 days after the spring freeze cleared.
How long is the growing season in Unionville?
Measured between 28°F hard freezes, Unionville sees about 203 frost-free days — roughly Apr 11 through Oct 31, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 2 to Oct 17, about 168 days.
Is the soil safe to grow vegetables in Unionville?
The federal record around Unionville is a meaningful one — 484 documented sites, mostly Underground Storage Tanks entries (230), the nearest Nitrate record about 1.6 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 Oct 1 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 31 (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 31. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Unionville's scale — its 6b band and its 203-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 ~203-day season between 28°F freezes, the 156 acres it covers and 484 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Unionville's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Unionville's own 28°F hard-freeze dates, about Apr 11 and Oct 31 and the ~203-day span between themNOAA 1991–2020 Climate Normals
- 484 documented contamination sites on the federal record near Unionville, the closest Nitrate record about 1.6 miles out from the town centreFederal environmental registers
- Unionville's boundary and the 156 acres inside itUS Census TIGER/Line 2025
- Which of 1,085 plants clear zones 6b and a ~203-day seasonGrowable Ground crop-matching engine
- The ecoregion at Unionville's own centroid, the Ridge and ValleyUS 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 156 acres read through its county's SSURGO summaryfrom Centre County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Centre 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 Centre County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Unionville's 156 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 156 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 1.6 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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