Mercer, Pennsylvania, sits in USDA hardiness zone 6a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Expect cabbage, hazelnut, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Mercer, 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 Mercer 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 Mercer — soil, climate, flood, and parcel records. How we handle your address.
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Mercer — the short answer
Mercer, Pennsylvania: USDA zone 6a, about 196 days between hard freezes, across 740 acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~196
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 740 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 Mercer's average, not your lot's — a low corner or a tree line moves it. Against Mercer's 196-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Mercer
Each reading below is measured for Mercer itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMercer runs about 196 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
MeasuredMercer 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 Mercer is in
Mercer sits in the Erie Drift Plain — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Mercer's own centroid rather than borrowed from Mercer County.
What Grows in Mercer
Every plant below cleared Mercer's own zone 6a and its 196-day season. Each card opens that plant's Pennsylvania profile. How we score.
Is it too late to plant in Mercer?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 23; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 20 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 2 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
Documented around Mercer
Spotted lanternfly documented 2 miles from Mercer, first recorded 2022. What to watch for.
What's on the federal record near Mercer
Closest first, within ~10 miles of Mercer. Listing isn't leaking, and distance isn't exposure.
- BEN BISSETT CHEVY OLDSUnderground Storage Tanks · 650 ft
- BISSETT CHEVROLETBrownfields · 700 ft
- MERCER SCIUnderground Storage Tanks · 700 ft
- SCH BUS GARAGEUnderground Storage Tanks · 800 ft
- WATSONS FEED SVCUnderground Storage Tanks · 800 ft
- ROBERT A POOLEUnderground Storage Tanks · 800 ft
- KENNETH SWARTZUnderground Storage Tanks · 800 ft
- MERCER CNTY LIVING CTRUnderground Storage Tanks · 800 ft
- ENG DIST 1 0Underground Storage Tanks · 800 ft
- BP OILUnderground Storage Tanks · 800 ft
- GABIGS SVCUnderground Storage Tanks · 1000 ft
- SUBURBAN PROPANE MERCERUnderground Storage Tanks · 1000 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Mercer'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 Mercer.
Total Sites
319
within ~10 miles of Mercer
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Mercer
Severity Distribution
within ~10 miles of Mercer
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mercer, two things run higher than the national average within ~10 miles of Mercer — Nitrate (102 sites) and PFAS (3 sites). That's not a problem with your land — it's information about it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Mercer
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 Mercer average
Your land is one point inside Mercer
Everything above resolves to Mercer as a whole — one PHZM band and one 28°F frost record, read across 740 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 Mercer Average
Mercer Average
- ●USDA Zones 6a, averaged across Mercer
- ●One soil character for all of Mercer
- ●Frost dates read at Mercer's scale: Apr 20 to Nov 2
YOUR Parcel
- ✓Your exact zone, not Mercer's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Mercer
Pull a site-specific report for your exact address in Mercer, Pennsylvania — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mercer averages can't show:
We read public map data around Mercer — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mercer average
How we know this about Mercer
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 Mercer’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 Mercer
When does frost risk typically end in Mercer?
The last hard freeze (28°F) in Mercer typically lands around Apr 20, 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 11.
When is the first frost in Mercer?
The first hard freeze (28°F) in Mercer typically arrives around Nov 2, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 19, so the watching starts about Oct 3 — about 196 days after the spring freeze cleared.
How long is the growing season in Mercer?
Measured between 28°F hard freezes, Mercer sees about 196 frost-free days — roughly Apr 20 through Nov 2, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 11 to Oct 19, about 161 days.
Is the soil safe to grow vegetables in Mercer?
The federal record around Mercer is a meaningful one — 319 documented sites, mostly Underground Storage Tanks entries (126), the nearest Underground Storage Tanks record about 0.1 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 Mercer?
From about Oct 3 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 Nov 2 (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 Nov 2. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Mercer's scale — its 6a band and its 196-day season. Your yard writes its own version of Mercer'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 Mercer’s own scale
7 of the readings below were taken at Mercer's own scale — its own ~196-day season between 28°F freezes, the 740 acres it covers and 319 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Mercer's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Mercer's own 28°F hard-freeze dates, about Apr 20 and Nov 2 and the ~196-day span between themNOAA 1991–2020 Climate Normals
- 319 documented contamination sites on the federal record near Mercer, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Mercer's boundary and the 740 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~196-day seasonGrowable Ground crop-matching engine
- The ecoregion at Mercer's own centroid, the Erie Drift PlainUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Mercerlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Mercer's 740 acres read through its county's SSURGO summaryfrom Mercer County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Mercer 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 Mercer County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Mercer's 740 acreswhy one lot differs from the next →
- Which side of Mercer you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 740 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Mercer-wide figureread your own land →
More in Pennsylvania
Wider growing context
What grows across PennsylvaniaMercer sits outside our named growing regions, so Pennsylvania as a whole is its closest context here.
Nearby growing guides