Horsham, Pennsylvania, sits in USDA hardiness zone 7a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
A short list that earns its place here — cabbage, hazelnut, california poppy, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Horsham, 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 Horsham 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 Horsham — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Horsham — the short answer
Horsham, Pennsylvania: USDA zone 7a, about 232 days between hard freezes, across 4K acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 28
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~232
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 4K 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 7a is Horsham's average, not your lot's — a low corner or a tree line moves it. Against Horsham's 232-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Horsham
Each reading below is measured for Horsham itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHorsham runs about 232 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
MeasuredHorsham sits in USDA hardiness zone 7a.
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 Horsham is in
Horsham sits in the Northern Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Horsham's own centroid rather than borrowed from Montgomery County.
What Grows in Horsham
Every plant below cleared Horsham's own zone 7a and its 232-day season. Each card opens that plant's Pennsylvania profile. How we score.
Is it too late to plant in Horsham?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Feb 28; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 28 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 15 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
Documented around Horsham
Spotted lanternfly documented 2 miles from Horsham, first recorded 2018. What to watch for.
What's on the federal record near Horsham
Closest first, within ~10 miles of Horsham. Listing isn't leaking, and distance isn't exposure.
- KLENKS COLLISION/HORSHAMBrownfields · 600 ft
- RYDER TRANSP SVC 1079AUnderground Storage Tanks · 950 ft
- EAGLE INDUSTRIAL HYGIENEBrownfields · 1700 ft
- DREXEL INDUnderground Storage Tanks · 1700 ft
- DREXEL IND INCToxics Release Inventory · 1700 ft
- LUKOIL 69230Underground Storage Tanks · 2000 ft
- STAN & BRADS TURNPIKE AUTOBrownfields · 2100 ft
- CLAYTONS HUNTING & FISHING INCBrownfields · 2300 ft
- HORSHAM GULFUnderground Storage Tanks · 2300 ft
- TAYLOR RENTAL CTRUnderground Storage Tanks · 2400 ft
- BUX MONT AUTOBrownfields · 2400 ft
- WAWA FOOD MARKET #271Brownfields · 2600 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Horsham'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 Horsham.
Sources Checked
within ~10 miles of Horsham
Severity Distribution
within ~10 miles of Horsham
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.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Horsham
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 Horsham average
Your land is one point inside Horsham
Everything above resolves to Horsham as a whole — one PHZM band and one 28°F frost record, read across 4K 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 Horsham Average
Horsham Average
- ●USDA Zones 7a, averaged across Horsham
- ●One soil character for all of Horsham
- ●Frost dates read at Horsham's scale: Mar 28 to Nov 15
YOUR Parcel
- ✓Your exact zone, not Horsham's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Horsham
Pull a site-specific report for your exact address in Horsham, Pennsylvania — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Horsham averages can't show:
We read public map data around Horsham — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Horsham average
How we know this about Horsham
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 Horsham’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 Horsham
When does frost risk typically end in Horsham?
The last hard freeze (28°F) in Horsham typically lands around Mar 28, 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 Apr 18.
When is the first frost in Horsham?
The first hard freeze (28°F) in Horsham typically arrives around Nov 15, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 1, so the watching starts about Oct 16 — about 232 days after the spring freeze cleared.
How long is the growing season in Horsham?
Measured between 28°F hard freezes, Horsham sees about 232 frost-free days — roughly Mar 28 through Nov 15, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 18 to Nov 1, about 197 days.
Is the soil safe to grow vegetables in Horsham?
The federal record around Horsham runs heavier than most — 3,046 documented sites, mostly Underground Storage Tanks entries (1,505), the nearest Brownfields record about 0.1 miles out — 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 Horsham?
From about Oct 16 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 15 (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 15. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Horsham's scale — its 7a band and its 232-day season. Your yard writes its own version of Horsham'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 Horsham’s own scale
7 of the readings below were taken at Horsham's own scale — its own ~232-day season between 28°F freezes, the 3,501 acres it covers and 3,046 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Horsham's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Horsham's own 28°F hard-freeze dates, about Mar 28 and Nov 15 and the ~232-day span between themNOAA 1991–2020 Climate Normals
- 3,046 documented contamination sites on the federal record near Horsham, the closest Brownfields record about 0.1 miles out from the town centreFederal environmental registers
- Horsham's boundary and the 3,501 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~232-day seasonGrowable Ground crop-matching engine
- The ecoregion at Horsham's own centroid, the Northern PiedmontUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Horshamlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Horsham's 3,501 acres read through its county's SSURGO summaryfrom Montgomery County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Montgomery 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 Montgomery County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Horsham's 3,501 acreswhy one lot differs from the next →
- Which side of Horsham you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,501 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Horsham-wide figureread your own land →
More in Pennsylvania
Wider growing context
What grows across PennsylvaniaHorsham sits outside our named growing regions, so Pennsylvania as a whole is its closest context here.
Nearby growing guides