Leonardtown, Maryland, sits in USDA hardiness zone 7b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
On paper, cabbage, prickly pear, california poppy, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Leonardtown, 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 Leonardtown 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 Leonardtown — soil, climate, flood, and parcel records. How we handle your address.
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Leonardtown — the short answer
Leonardtown, Maryland: USDA zone 7b, about 253 days between hard freezes, across 2K acres of town.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 18
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~253
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 2K 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 7b is Leonardtown's average, not your lot's — a low corner or a tree line moves it. Against Leonardtown's 253-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Leonardtown
Each reading below is measured for Leonardtown itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredLeonardtown runs about 253 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
MeasuredLeonardtown sits in USDA hardiness zone 7b.
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 Leonardtown is in
Leonardtown sits in the Southeastern Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Leonardtown's own centroid rather than borrowed from St. Mary's County.
What Grows in Leonardtown
Every plant below cleared Leonardtown's own zone 7b and its 253-day season. Each card opens that plant's Maryland profile. How we score.
Is it too late to plant in Leonardtown?
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 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 18 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 26 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
Documented around Leonardtown
Spotted lanternfly documented 11 miles from Leonardtown, first recorded 2019. What to watch for.
What's on the federal record near Leonardtown
Closest first, within ~10 miles of Leonardtown. Listing isn't leaking, and distance isn't exposure.
- Carolyn G. DucoteUnderground Storage Tanks · 1600 ft
- Edward CusicUnderground Storage Tanks · 1600 ft
- Ragan, GordonUnderground Storage Tanks · 1600 ft
- Payne & Sons, Inc.Underground Storage Tanks · 1600 ft
- St. Mary's County-Dept of Recreation & ParksUnderground Storage Tanks · 1600 ft
- Miedzinski TransferUnderground Storage Tanks · 1600 ft
- John Lynch, Jr.Underground Storage Tanks · 1600 ft
- Lester Mattingly & SonsUnderground Storage Tanks · 1600 ft
- Guy District Co.Underground Storage Tanks · 1600 ft
- Besche Oil Company, Inc./Leonardtown PlantUnderground Storage Tanks · 1600 ft
- Guy & Guy Masonry, Inc.Underground Storage Tanks · 1600 ft
- MEDSTAR ST. MARYS HOSPITALBrownfields · 1700 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Leonardtown'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 Leonardtown.
Sources Checked
within ~10 miles of Leonardtown
Severity Distribution
within ~10 miles of Leonardtown
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Leonardtown, Nitrate runs higher than the national average — 126 sites within ~10 miles of Leonardtown. 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 Leonardtown
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 Leonardtown average
Your land is one point inside Leonardtown
Everything above resolves to Leonardtown as a whole — one PHZM band and one 28°F frost record, read across 2K 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 Leonardtown Average
Leonardtown Average
- ●USDA Zones 7b, averaged across Leonardtown
- ●One soil character for all of Leonardtown
- ●Frost dates read at Leonardtown's scale: Mar 18 to Nov 26
YOUR Parcel
- ✓Your exact zone, not Leonardtown's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Leonardtown
Pull a site-specific report for your exact address in Leonardtown, Maryland — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Leonardtown averages can't show:
We read public map data around Leonardtown — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Leonardtown average
How we know this about Leonardtown
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 Leonardtown’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 Leonardtown
When does frost risk typically end in Leonardtown?
The last hard freeze (28°F) in Leonardtown typically lands around Mar 18, 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 8.
When is the first frost in Leonardtown?
The first hard freeze (28°F) in Leonardtown typically arrives around Nov 26, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 12, so the watching starts about Oct 27 — about 253 days after the spring freeze cleared.
How long is the growing season in Leonardtown?
Measured between 28°F hard freezes, Leonardtown sees about 253 frost-free days — roughly Mar 18 through Nov 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 8 to Nov 12, about 218 days.
Is the soil safe to grow vegetables in Leonardtown?
The federal record around Leonardtown is a meaningful one — 418 documented sites, mostly Underground Storage Tanks entries (203), the nearest Underground Storage Tanks record about 0.3 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 Leonardtown?
From about Oct 27 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 26 (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 26. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Leonardtown's scale — its 7b band and its 253-day season. Your yard writes its own version of Leonardtown'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 Leonardtown’s own scale
7 of the readings below were taken at Leonardtown's own scale — its own ~253-day season between 28°F freezes, the 2,464 acres it covers and 418 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Leonardtown's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Leonardtown's own 28°F hard-freeze dates, about Mar 18 and Nov 26 and the ~253-day span between themNOAA 1991–2020 Climate Normals
- 418 documented contamination sites on the federal record near Leonardtown, the closest Underground Storage Tanks record about 0.3 miles out from the town centreFederal environmental registers
- Leonardtown's boundary and the 2,464 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~253-day seasonGrowable Ground crop-matching engine
- The ecoregion at Leonardtown's own centroid, the Southeastern PlainsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Leonardtownlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Leonardtown's 2,464 acres read through its county's SSURGO summaryfrom St. Mary's County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom St. Mary's County
- The growing challenges every Maryland grower plans around — written at state scale, so they stay on the state guidefrom Maryland
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom St. Mary's County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Leonardtown's 2,464 acreswhy one lot differs from the next →
- Which side of Leonardtown you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,464 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.3 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 Leonardtown-wide figureread your own land →
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