Maryland spans USDA hardiness zones 5b-8a, with a growing season of about 238 frost-free days — a long runway that turns one growing season into what colder regions would call two.
Those zone numbers rest on 36-48 inches of annual rainfall, a median of roughly 3,789 growing-degree days (base 50°F), and about 2,500 winter chill hours for tree fruit — the measurements that do the deciding. Soils here lean toward silt loam, clay, sandy loam (Eastern Shore), and Piedmont clay, and each drains differently — the single trait that most often decides whether a crop takes hold. Zoom in and Maryland resolves into Appalachia, Tidewater & Chesapeake, and Delmarva Peninsula — distinct growing regions with distinct frost calendars. On paper, tomato, black-eyed susan, peach, and sweet corn all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Grounded inUSDA PHZM•NOAA Climate Normals•USDA NRCS SSURGO•GDD (PRISM 1991-2020 normals)•Chill hours (PRISM 1991-2020 normals)•USDA hardiness sub-region map•EPA FRS•USDA PLANTS•Growable Ground suitability scoring
Maryland spans zones 5b-8a, but your yard 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 — soil, climate, flood, and parcel records. How we handle your address.
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Distinct growing regions within Maryland — each has its own zones, soils, and signature crops.
Maryland: USDA zones 5b-8a, 190–270 frost-free days depending on the county, 24 counties.
The middle half of this state’s counties. Tender transplants usually wait 2–3 weeks past the last hard freeze. The shortest-season figure is Maryland's own county record — Garrett County's measured 28°F normal, not a modeled floor.
Maryland does not have one growing season. Across all 526 of its towns that carry their own 30-year record, the shortest measured season is Gorman's at 170 days and the longest is Romancoke's at 278 — a 108-day spread inside one state.
Neither end is a lone reading — another 7 towns measure within 10 days of Gorman and 33 sit within 10 days of Romancoke. These are real pockets, so the number to plant against is your own town's, not the state average.
NOAA Regional Climate Centers ACIS (1991–2020), 30-year daily minimum record
Zone 5b-8a is Maryland's average, not your lot's — a low corner or a tree line moves it. Against Maryland's 238-day season, see what your own ground reads.
One answer for Maryland averages 24 counties whose growing seasons are 80 days apart — from 190 frost-free days in Garrett County to 270 in Talbot County. That is the same state, measured the same way, in the same years. Which end of it your county sits nearer decides what finishes before the first hard freeze.
The middle half of 24 counties runs 225–255 days, with a median of 237 days — a 80-day span end to end.
Measured across 24 counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. A county with no record of its own is absent from the range rather than counted as zero — nothing here is interpolated to the state. Your own site sits somewhere inside this range; a parcel report resolves where.
The middle half of Maryland runs 225–255 frost-free days, and 11 of its 24 counties sit outside that — 5 on the short side, 6 on the long. A statewide planting date describes the middle well and the ends poorly, which is worth knowing before you follow one.
Under 225 frost-free days
5 counties
3 of 5 shown
The end of the state that sets the planting calendar — start seed indoors here and the season stretches to meet the crop.
225–255 frost-free days
13 counties
0 of 13 shown
The middle half of the state, and the part a single statewide date describes well.
Over 255 frost-free days
6 counties
3 of 6 shown
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, county 28°F killing freeze), the same figure its own guide page publishes. Elevation, slope and cold-air drainage move a yard within its county as well — which is the part only your address resolves.
The soil types that dominate Maryland — how each drains decides more about crop success than almost anything else. Tap any soil to learn what it is and how to work with it. Each photo is a representative profile of that soil type; the named series is where it was documented, which is often another state.
Drainage
Moderate. Silt holds water well and releases it steadily, though the fine particles can crust after hard rain and compact under traffic.
What thrives
The full vegetable garden does well here, and small grains, corn, and leafy greens are classic silt-loam crops. Its steady moisture suits shallow-rooted plants that dislike drought stress.
Drainage
Slow. Water enters clay reluctantly and leaves it the same way, so wet springs keep it cold and unworkable longer than lighter soils.
What thrives
Once established, heavy feeders prosper — brassicas, beans, corn, and many fruit trees ride clay’s nutrient supply and summer moisture reserve. Daylilies, roses, and prairie perennials handle it without complaint.
Drainage
Fast. The sand fraction opens the soil up, so water moves through the root zone quickly and the surface rarely stays soggy. The trade is that nutrients ride out with the water.
What thrives
Root crops love it — carrots, potatoes, radishes, and onions size up cleanly in ground they can push through. Melons, sweet potatoes, asparagus, and most herbs appreciate the warmth and the drainage.
Drainage
Slow. Red clay seals under pounding rain and sheds water across the surface, then holds tight to what soaks in.
What thrives
Okra, southern peas, sweet potatoes, and muscadines are traditional red-clay performers, and many fruit trees root deep into it once through the first year. Azaleas and blueberries appreciate its typical acidity.
Soil data: USDA NRCS SSURGO · Soil types explained
Plants well-suited to Maryland's climate, soils, and growing season — each links to its full growing profile.
Usually not — gardeners here simply switch what goes in the ground as the season moves. Across Maryland, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Mar 24, with the middle half of counties between Mar 18 and Mar 29 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Nov 11 and Nov 27 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
The plants Maryland put its name on — cultural emblems, not growing recommendations.
Rudbeckia hirta
Designated 1918. In our plant library — see its full growing profile.
Quercus alba
Designated 1941. In our plant library — see its full growing profile.
Plants the USDA PLANTS Database documents as native and present in Maryland — a real per-state range, not just a zone match. Ordered by how closely each plant’s published hardiness range matches Maryland’s zones 5b-8a, so this is a shortlist by climate fit, not a ranking of which plants matter most here. Presence is statewide, so a plant may still be uncommon in your specific county; your state’s Cooperative Extension or a native-plant society is the local authority.
US-native plants whose hardiness range overlaps Maryland’s USDA zones 5b-8a but which USDA PLANTS doesn’t map to a single state range here. Zone overlap is a starting filter, not a range map.
What an experienced grower plans around here — each one has a move.
Heavy Piedmont clay drains poorly
A raised bed today, compost every fall — Piedmont clay becomes an asset once the drainage is yours.
Humidity and heat in summer promote disease
Morning watering at the base, room to breathe between plants, resistant varieties — the humid-summer basics, per your extension.
Deer pressure in suburban areas is extreme
A tall fence is the answer that holds; for everything outside it, lean toward the plants deer reliably skip.
For cultivar selection, pest pressure, and planting-time guidance specific to Maryland, the University of Maryland Extension is the authoritative local source.
Safe to Grow Here?What the federal record shows across Maryland — and how to grow with it.
We checked the federal record across Maryland — 28,014 documented sites across 8 of the 9 source types we track.
The most significant on record: 167 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Maryland carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Severity Distribution
across Maryland
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Maryland, CAFO runs higher than the national average — 623 sites across Maryland. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Everything above resolves to Maryland as a whole — a state whose own counties record seasons 80 days apart, and hardiness across zones 5b-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 state 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 statewide average.
State averages sketch the shape. Your soil, sun exposure, drainage, and microclimate decide what actually takes. Pull a site-specific report for your exact parcel.
Enter your address. We read your soil, sun, drainage, and frost dates, then score 1,086 plants against the real conditions on your land.
Three things about your lot that Maryland averages can't show:
We read public map data around Maryland — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Maryland average
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read per county and aggregated to the state band; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each county’s own record; rainfall from NOAA Climate Normals; soils from USDA NRCS SSURGO; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above. Where a county carries no record of its own, it is absent from the figure rather than filled in.
Maryland spans USDA hardiness zones 5b-8a — which is to say winter's coldest night runs from about −15°F to 15°F depending where in Maryland you are, averaged over 1991–2020 (USDA PHZM 2023).
Usually not — gardeners here simply switch what goes in the ground as the season moves. Across Maryland, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Mar 24, with the middle half of counties between Mar 18 and Mar 29 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Nov 11 and Nov 27 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
Across Maryland, the middle half of counties see their last hard freeze (28°F) between about Mar 18 and Mar 29, with a county median near Mar 24 (NOAA 1991–2020 climate normals). 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 14.
Measured between 28°F hard freezes, growing seasons across Maryland's counties mostly run about 227 to 256 days, with a county median near 238 (NOAA 1991–2020 climate normals). Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
Maryland's zones 5b-8a support a wide range — strong performers include Tomato, Black-eyed Susan, Peach, Sweet Corn, and Crab Apple. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Officially, Maryland spans USDA zones 5b-8a (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,086 plants against what's actually there.
The federal record across Maryland runs heavier than most — 28,014 documented sites, mostly Underground Storage Tanks entries (12,667) — 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.
Start with three facts. Maryland spans USDA zones 5b-8a, which sets what survives winter; last hard freezes range from about Mar 18 to Mar 29 across its counties (NOAA 1991–2020 climate normals); and 28,014 documented sites sit on the federal record here, so a soil test before food beds is the smart first step. From there, matching plants to your actual soil and sun is the fun part.
Everything above is measured at Maryland's scale — its 5b-8a band and its 238-day season. Your yard writes its own version of Maryland's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
6 of the readings below were taken at Maryland's own scale — the full zone 5b-8a span inside its borders, the 4 soil types that dominate its ground and 28,014 documented sites on its federal record; anything it cannot resolve at this scale is named below.
Measured here
What this page can’t tell you
Explore growing conditions by county — each has its own zone range and land area.
Explore growing conditions by city or town in Maryland.
Maryland shares its dominant growing region with these states — a useful comparison if you're weighing where a crop will behave the same way.
