The Maryland Piedmont spans USDA hardiness zones 7a-8a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Maryland's crystalline-rock foothill belt between the fall line and the Blue Ridge — heavy clay and silt loams over ancient bedrock, later spring frosts, and a roughly 217–234-day inland season that sets it apart from the sandy Delmarva coast and the cold western mountains. (EPA Northern Piedmont, ecoregion 64 — a separate region from the southern Piedmont; Baltimore City runs a zone warmer as an urban heat island.) The conditions favor tomato, sweet corn, peach, and crab apple, among others — though every individual site edits that list with its own soil, sun, and drainage.
The Maryland Piedmont spans Maryland.
Your yard isn't all of the Maryland Piedmont.
The Maryland Piedmont spans USDA zones 7a-8a, 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 Maryland Piedmont — soil, climate, flood, and parcel records. How we handle your address.
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The Maryland Piedmont — the short answer
The Maryland Piedmont: USDA zones 7a-8a, 217–260 frost-free days depending where in it you stand, in Maryland.
- USDA zones
- 7a-8a
- USDA PHZM 2023, aggregated over the footprint
- Shortest season here
- 217 days
- NOAA Regional Climate Centers ACIS, 1991-2020 — Howard County
- Counties
- 7
- 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. The season figure is this region's own record, measured across its 7 member counties, not a state or national average.
Hardiness Zone Range
The Maryland Piedmont is not one growing season
One answer for the Maryland Piedmont averages 7 counties whose growing seasons are 43 days apart — from 217 frost-free days in Howard County to 260 in Baltimore County. That is the same region, measured the same way, in the same years. Which end of it your land sits nearer decides what finishes before the first hard freeze.
The middle half of 7 counties runs 224–231 days, with a median of 227 days — a 43-day span end to end.
Measured across 7 member counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020. A member with no own record is absent from the range rather than counted as zero — nothing here is interpolated to the region. Your own site sits somewhere inside this range; a parcel report resolves where.
Where the line runs inside the Maryland Piedmont
The middle half of the Maryland Piedmont runs 224–231 frost-free days, and 4 of its 7 counties sit outside that — 2 on the short side, 2 on the long. A regional planting date describes the middle well and the ends poorly, which is worth knowing before you follow one.
Under 224 frost-free days
2 counties
- Howard County · 217 days
- Frederick County · 223 days
The end of the region that sets the planting calendar — start seed indoors here and the season stretches to meet the crop.
224–231 frost-free days
3 counties
0 of 3 shown
The middle half of the region, and the part a single regional season describes well.
Over 231 frost-free days
2 counties
- Baltimore County · 260 days
- Baltimore County · 234 days
Long enough for a second succession of a quick crop after the first comes out.
Each county is placed by its OWN 28°F frost-free normal (NOAA Regional Climate Centers ACIS, 1991-2020), the same figure its own guide page publishes. Elevation, slope and cold-air drainage move a site within its county as well — which is the part only your address resolves.
What Grows in the Maryland Piedmont
All 2 of the plants below that publish a season requirement clear even Howard County’s 217 frost-free days — so on season alone, this grid works at both ends of the region. The 43-day spread still decides how far past this list you can push, and how early you can start.
Plants matched to the Maryland Piedmont's USDA zones 7a-8a, 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 Maryland Piedmont
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets the Maryland Piedmont’s USDA zones 7a-8a — 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 Maryland Piedmont
The USDA soil survey maps this ground county by county. These are those records weighted by land area across seven member counties — this region’s own profile, not a state figure.
The ground is predominantly Ultisols, at 52% of mapped acres, followed by Alfisols (23%), Inceptisols (20%) and Entisols (4%). Seven 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 Glenelg, Manor, and Brinklow.
70% of those acres are well drained, and another 12% moderately well drained, 5% poorly drained. Topsoil pH runs 4.6–6.2 between the lowest and the highest county on record. 31% of the footprint is classed prime farmland.
Soil order
Ultisols
Drainage
Well drained
Topsoil pH
4.6–6.2
Hydric soils
7%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. Harford County holds the most wetland ground here, at 10% — soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Maryland Piedmont
The soil survey reads this ground county by county, and the readings above are those records summed across the Maryland Piedmont. Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records70% of the mapped acres across the Maryland Piedmont are well drained — ground that drains quickly. That is area-weighted across all seven 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 Maryland Piedmont runs pH 4.6–6.2 — acidic in all seven 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 Maryland Piedmont — and how to grow with it.
Across the Maryland Piedmont's 7 counties the federal record holds 13,418 documented sites, mostly Underground Storage Tanks (6,029), Brownfields (4,866) and Nitrate (1,958). The heaviest single county is Baltimore County, with 3,433.
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 Maryland Piedmont to see which records sit where you actually grow.
Sources Checked
Summed across the 7 counties in the Maryland Piedmont
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 Maryland Piedmont
Everything above resolves to the Maryland Piedmont as a whole — a footprint whose own counties record seasons 43 days apart, and hardiness across zones 7a-8a. Your parcel sits at one point in that range, not in the middle of it. 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 Maryland Piedmont Average
Maryland Piedmont Average
- ●USDA Zones 7a-8a, averaged across Maryland Piedmont
- ●One soil character for all of Maryland Piedmont
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Maryland Piedmont's 7a-8a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Maryland Piedmont
Pull a site-specific report for your exact address in the Maryland Piedmont — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Maryland Piedmont averages can't show:
We read public map data around The Maryland Piedmont — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Maryland Piedmont average
How we know this about the Maryland Piedmont
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 Maryland Piedmont
What hardiness zone is the Maryland Piedmont?
The Maryland Piedmont spans USDA hardiness zones 7a-8a, 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 Maryland Piedmont?
Measured between 28°F hard freezes, the Maryland Piedmont's counties mostly run 224 to 231 frost-free days, median 227 (NOAA Regional Climate Centers ACIS, 1991–2020, over 7 member counties). That 7-day spread is the honest read — no single season describes 7 counties, and each county guide below carries its own.
When does frost risk end in the Maryland Piedmont?
Across the Maryland Piedmont, the middle half of member counties see their last 28°F hard freeze between Mar 27 and Mar 30 (median Mar 29), and their first fall freeze between Nov 9 and Nov 13. Those are hard freezes, not the last light frost: tender transplants wait for about Apr 19, and elevation decides which end of a 3-day spread you garden in.
What grows well in the Maryland Piedmont?
The Maryland Piedmont's conditions suit plants such as Tomato, Sweet Corn, Peach, Crab Apple, Black-eyed Susan. 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 Maryland Piedmont defined?
The Maryland Piedmont is defined here as a curated cluster of 7 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 Maryland Piedmont cover?
The Maryland Piedmont spans Maryland. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Appalachia, Tidewater & Chesapeake, Delmarva Peninsula, Cumberland Valley, and Southern Maryland share at least one state with the Maryland Piedmont. 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 Maryland Piedmont’s own scale
6 of the readings below were taken at the Maryland Piedmont's own scale — the zone 7a-8a band across its footprint, a median 227-day season across its 7 counties and 13,418 documented federal contamination records across its 7 counties, 3,433 of them in Baltimore County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 7a-8a aggregated across all 7 counties in the footprintUSDA PHZM 2023
- The boundary itself — the 7 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 7 counties run 224 to 231 frost-free days, median 227NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 13,418 documented federal contamination records across its 7 counties, 3,433 of them in Baltimore County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 52% Ultisols, topsoil pH 4.6–6.2, area-weighted across its 7 mapped countiesUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 7a-8afrom Maryland
What this page can’t tell you
- Which end of the 7-day range your ground sits at — 224 days at one extreme, 231 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 Maryland Piedmont
State growing guides
Counties in this region
Other growing regions across Maryland
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.)
The low, flat, tidal coastal plain around Chesapeake Bay — sandy soils, mild maritime winters, and a long season for vegetables and Southern staples.
A flat coastal-plain peninsula of sandy, well-drained soils between the Chesapeake and the Atlantic — a major sweet-corn, soybean, and produce region.
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.
Southern Maryland is the Western Shore's warm corner — the tri-county Potomac–Chesapeake peninsula (Calvert, Charles, St. Mary's) that the Eastern Shore's Delmarva and Tidewater pages never reach. Tempered on three sides by tidal water on light coastal-plain soils, it runs a zone warmer and roughly a month longer than the Piedmont just to the north: zone 8a with 264 frost-free days in Calvert and 263 in St. Mary's, easing to 7b and 238 days inland in Charles. First frost holds off until early December on the shore (Dec 3 in Calvert, Dec 2 in St. Mary's) with milder winters than Baltimore or Frederick — historic tobacco country that now favors figs, long-season tomatoes, and a real fall greens window.