The Lehigh Valley spans USDA hardiness zone 7a — a zone band wide enough that plant choice, not possibility, is the interesting question.
The Lehigh Valley — Lehigh and Northampton counties, the two-county region overseen by the Lehigh Valley Planning Commission — sits entirely in USDA hardiness zone 7a with a growing season of roughly 209 to 212 frost-free days. These conditions suit tomato, mountain laurel, apple, and grape — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
The Lehigh Valley spans Pennsylvania.
Your yard isn't all of the Lehigh Valley.
The Lehigh Valley spans USDA zones 7a, but your parcel sits in exactly one — and slope, tree cover, and low spots nudge it further. 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 Lehigh Valley — soil, climate, flood, and parcel records. How we handle your address.
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The Lehigh Valley — the short answer
The Lehigh Valley: USDA zones 7a, 209–212 frost-free days, in Pennsylvania.
- USDA zones
- 7a
- USDA PHZM 2023, aggregated over the footprint
- Frost-free season
- 209–212 days
- NOAA Regional Climate Centers ACIS, 1991-2020
- Counties
- 2
- US Census TIGER/Line 2025
- Region type
- County cluster
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. Where a region publishes no measured season, no season figure is shown.
Hardiness Zone Range
What Grows in the Lehigh Valley
Plants matched to the Lehigh Valley's USDA zones 7a, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of the Lehigh Valley
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets the Lehigh Valley’s USDA zones 7a — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground across the Lehigh Valley
The USDA soil survey maps this ground county by county. These are those records weighted by land area across two member counties — this region’s own profile, not a state figure.
The ground is predominantly Inceptisols, at 44% of mapped acres, followed by Alfisols (30%), Ultisols (23%) and Entisols (3%). Five soil orders appear somewhere inside the footprint, which is the honest reason a regional soil answer only goes so far. The most extensive named soils are Berks, Washington, and Gladstone.
65% of those acres are well drained, and another 9% moderately well drained, 6% poorly drained. Topsoil pH runs 5.1–6.5 between the lowest and the highest county on record. 28% of the footprint is classed prime farmland.
Soil order
Inceptisols
Drainage
Well drained
Topsoil pH
5.1–6.5
Hydric soils
6%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. Northampton County holds the most wetland ground here, at 7% — soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Lehigh Valley
The soil survey reads this ground county by county, and the readings above are those records summed across the Lehigh Valley. Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records65% of the mapped acres across the Lehigh Valley are well drained — ground that drains quickly. That is area-weighted across all two of its mapped counties.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
From county recordsTopsoil across the Lehigh Valley runs pH 5.1–6.5 — acidic in all two of them.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Safe to Grow Here?
What the federal record shows across the Lehigh Valley — and how to grow with it.
Across the Lehigh Valley's 2 counties the federal record holds 3,144 documented sites, mostly Underground Storage Tanks (1,614), Brownfields (922) and Nitrate (380). The heaviest single county is Lehigh County, with 1,843.
That is a regional count, not a reading of any one lot — proximity to a documented site is information, not a diagnosis. Open the map outlined to the Lehigh Valley to see which records sit where you actually grow.
Sources Checked
Summed across the 2 counties in the Lehigh Valley
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.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside the Lehigh Valley
Everything above resolves to the Lehigh Valley as a whole — a footprint spanning USDA zones 7a. Your parcel sits in exactly one of them. 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 region 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 regional average.
Your Lot vs the Lehigh Valley Average
Lehigh Valley Average
- ●USDA Zones 7a, averaged across Lehigh Valley
- ●One soil character for all of Lehigh Valley
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Lehigh Valley's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Lehigh Valley
Pull a site-specific report for your exact address in the Lehigh Valley — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Lehigh Valley averages can't show:
We read public map data around The Lehigh Valley — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Lehigh Valley average
How we know this about the Lehigh Valley
The boundary: a cluster of neighboring counties. Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the counties inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about the Lehigh Valley
What hardiness zone is the Lehigh Valley?
The Lehigh Valley spans USDA hardiness zones 7a, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's counties. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
How long is the growing season in the Lehigh Valley?
Measured between 28°F hard freezes, the Lehigh Valley's counties mostly run 210 to 211 frost-free days, median 211 (NOAA Regional Climate Centers ACIS, 1991–2020, over 2 member counties). That 1-day spread is the honest read — no single season describes 2 counties, and each county guide below carries its own.
When does frost risk end in the Lehigh Valley?
Across the Lehigh Valley, the middle half of member counties see their last 28°F hard freeze between Apr 5 and Apr 6 (median Apr 6), and their first fall freeze between Nov 2 and Nov 3. Those are hard freezes, not the last light frost: tender transplants wait for about Apr 27, and elevation decides which end of a 1-day spread you garden in.
What grows well in the Lehigh Valley?
The Lehigh Valley's conditions suit plants such as Tomato, Mountain Laurel, Apple, Grape, Mushroom. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is the Lehigh Valley defined?
The Lehigh Valley is defined here as a curated cluster of 2 neighboring counties that share a growing character. Growing regions have no official boundary, so this footprint is our published one — every county in it is named on this page.
Which states does the Lehigh Valley cover?
The Lehigh Valley spans Pennsylvania. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Appalachia, Northern Tier (north-central Pennsylvania high plateau), The Poconos, Cumberland Valley, Brandywine Valley, and Greater Philadelphia share at least one state with the Lehigh Valley. Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at the Lehigh Valley’s own scale
6 of the readings below were taken at the Lehigh Valley's own scale — the zone 7a band across its footprint, a median 211-day season across its 2 counties and 3,144 documented federal contamination records across its 2 counties, 1,843 of them in Lehigh County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 7a aggregated across all 2 counties in the footprintUSDA PHZM 2023
- The boundary itself — the 2 counties this region is curated fromGrowable Ground subregion registry
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The 28°F season across the footprint — the middle half of its 2 counties run 210 to 211 frost-free days, median 211NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 3,144 documented federal contamination records across its 2 counties, 1,843 of them in Lehigh County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 44% Inceptisols, topsoil pH 5.1–6.5, area-weighted across its 2 mapped countiesUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 7afrom Pennsylvania
What this page can’t tell you
- Which end of the 1-day range your ground sits at — 210 days at one extreme, 211 at the other, decided mostly by elevationfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore the Lehigh Valley
State growing guides
Counties in this region
Other growing regions across Pennsylvania
The vast eastern mountain region of steep hollows, thin acidic soils, and short upland seasons — apples, brambles, ramps, and forest crops on hard-won ground. (Union of the core Appalachian ecoregions.)
Pennsylvania's coldest, shortest-season ground: the glaciated high plateau of the North Central Appalachians (EPA Level III ecoregion 62), where Potter, Tioga, McKean, and Cameron counties all sit in USDA zone 5b with only 160-166 frost-free days — Potter's 160 is the state minimum, roughly five weeks shorter than Pennsylvania's median season. This is the "PA Wilds" / "God's Country" cold pocket: cold-air-pooling ridges and hollows, thin acidic plateau soils, and a last frost that holds into the first week of May. The generic multi-state Appalachia region spans a far milder 5b-8b across a 211-day median season and never resolves this plateau's short, cold window.
The Pocono Mountains of northeastern Pennsylvania — Carbon, Monroe, Pike, and Wayne counties — span USDA hardiness zones 6a to 6b with frost-free growing seasons of roughly 167 to 198 days.
The Cumberland Valley is the Great Valley's northern anchor — the same limestone floor that runs south into the Shenandoah, but colder-wintered and shorter-seasoned, and split by the Mason-Dixon line across Cumberland and Franklin counties in Pennsylvania and Washington County in Maryland. Scoped to just those three, the picture tightens to a uniform USDA zone 7a and a 215-to-219-day frost-free season — last frost in early April, first in early November — steadier than the wide 5b-8b range the broader Appalachian page has to average across. The valley reads in two halves: a flat limestone floor where cold air pools on clear spring nights, long given over to dairy pasture, hay, and grain, and the elevated Blue Ridge benches of South Mountain along the eastern edge, where good cold-air drainage has kept apple and peach orchards in business for generations. Those same well-drained slopes carry the federally recognized Cumberland Valley AVA's wine grapes.
The Brandywine Valley traces the Brandywine Creek watershed (USGS hydrologic unit 02040205) from Chester County, Pennsylvania into New Castle County, Delaware, spanning USDA zones 7a to 7b and a frost-free season of roughly 213 to 241 days.
Pennsylvania's only USDA zone 7b ground — the warmest, longest-season corner of the state. Philadelphia County runs about 250 frost-free days and Delaware County about 239, against a statewide county median of 197, so the tidal Delaware–Schuylkill corridor and the city's urban heat island buy growers here a full zone and roughly a month of extra season over the 7a suburbs just north. Last frost typically clears by mid-to-late March and first frost holds off until late November.