Harford, Pennsylvania, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Crops well matched to these conditions include cabbage, blackberry, california poppy, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Harford, 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 Harford 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 Harford — soil, climate, flood, and parcel records. How we handle your address.
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Harford — the short answer
Harford, Pennsylvania: USDA zone 6a, about 178 days between hard freezes, across 675 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 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~178
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 675 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 Harford's average, not your lot's — a low corner or a tree line moves it. Against Harford's 178-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Harford
Each reading below is measured for Harford itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHarford runs about 178 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
MeasuredHarford 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 Harford is in
Harford sits in the Northern Allegheny Plateau — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Harford's own centroid rather than borrowed from Susquehanna County.
What Grows in Harford
Every plant below cleared Harford's own zone 6a and its 178-day season. Each card opens that plant's Pennsylvania profile. How we score.
Is it too late to plant in Harford?
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 20 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
Documented around Harford
Spotted lanternfly documented 3 miles from Harford, first recorded 2019. What to watch for.
What's on the federal record near Harford
Closest first, within ~10 miles of Harford. Listing isn't leaking, and distance isn't exposure.
- SQ 36Nitrate · 1200 ft
- HMOUnderground Storage Tanks · 1200 ft
- SQ 461Nitrate · 0.6 mi
- LIBERTY TRUCK CTRUnderground Storage Tanks · 1.1 mi
- HARFORD PENN CAN TRAVEL PLAZAUnderground Storage Tanks · 1.2 mi
- SQ 125Nitrate · 1.4 mi
- SQ 177Nitrate · 1.5 mi
- SQ 120Nitrate · 1.7 mi
- SQ 150Nitrate · 2.1 mi
- SQ 133Nitrate · 2.7 mi
- ROSS FEEDS INCUnderground Storage Tanks · 2.8 mi
- MASTERS RMC INC KINGSLEY PLANTBrownfields · 2.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Harford'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 Harford.
Sources Checked
within ~10 miles of Harford
Severity Distribution
within ~10 miles of Harford
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Harford, Nitrate runs higher than the national average — 108 sites within ~10 miles of Harford. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Harford
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 Harford average
Your land is one point inside Harford
Everything above resolves to Harford as a whole — one PHZM band and one 28°F frost record, read across 675 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 Harford Average
Harford Average
- ●USDA Zones 6a, averaged across Harford
- ●One soil character for all of Harford
- ●Frost dates read at Harford's scale: Apr 25 to Oct 20
YOUR Parcel
- ✓Your exact zone, not Harford's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Harford
Pull a site-specific report for your exact address in Harford, Pennsylvania — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Harford averages can't show:
We read public map data around Harford — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Harford average
How we know this about Harford
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 Harford’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 Harford
When does frost risk typically end in Harford?
The last hard freeze (28°F) in Harford 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 Harford?
The first hard freeze (28°F) in Harford typically arrives around Oct 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 6, so the watching starts about Sep 20 — about 178 days after the spring freeze cleared.
How long is the growing season in Harford?
Measured between 28°F hard freezes, Harford sees about 178 frost-free days — roughly Apr 25 through Oct 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 16 to Oct 6, about 143 days.
Is the soil safe to grow vegetables in Harford?
The federal record around Harford is a meaningful one — 203 documented sites, mostly Nitrate entries (108), the nearest Nitrate 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 Harford?
From about Sep 20 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 20 (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 20. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Harford's scale — its 6a band and its 178-day season. Your yard writes its own version of Harford'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 Harford’s own scale
7 of the readings below were taken at Harford's own scale — its own ~178-day season between 28°F freezes, the 675 acres it covers and 203 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Harford's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Harford's own 28°F hard-freeze dates, about Apr 25 and Oct 20 and the ~178-day span between themNOAA 1991–2020 Climate Normals
- 203 documented contamination sites on the federal record near Harford, the closest Nitrate record about 0.2 miles out from the town centreFederal environmental registers
- Harford's boundary and the 675 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~178-day seasonGrowable Ground crop-matching engine
- The ecoregion at Harford's own centroid, the Northern Allegheny PlateauUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Harfordlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Harford's 675 acres read through its county's SSURGO summaryfrom Susquehanna County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Susquehanna 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 Susquehanna County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Harford's 675 acreswhy one lot differs from the next →
- Which side of Harford you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 675 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate 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 Harford-wide figureread your own land →
More in Pennsylvania
Wider growing context
What grows across PennsylvaniaHarford sits outside our named growing regions, so Pennsylvania as a whole is its closest context here.
Nearby growing guides