Williston, 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 Williston, 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 Williston 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 Williston — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Williston — the short answer
Williston, Maryland: USDA zone 7b, about 237 days between hard freezes, across 168 acres of town.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 24
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 16
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~237
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 168 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 Williston's average, not your lot's — a low corner or a tree line moves it. Against Williston's 237-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Williston
Each reading below is measured for Williston itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredWilliston runs about 237 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
MeasuredWilliston 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 Williston is in
Williston sits in the Middle Atlantic Coastal Plain — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Williston's own centroid rather than borrowed from Caroline County.
What Grows in Williston
Every plant below cleared Williston's own zone 7b and its 237-day season. Each card opens that plant's Maryland profile. How we score.
Is it too late to plant in Williston?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Feb 24; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 24 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 16 — 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.
Documented around Williston
Spotted lanternfly documented 2 miles from Williston, first recorded 2019. What to watch for.
What's on the federal record near Williston
Closest first, within ~10 miles of Williston. Listing isn't leaking, and distance isn't exposure.
- CO Ec 14Nitrate · 1000 ft
- Caroline Country ClubUnderground Storage Tanks · 1.3 mi
- ANDRE RANCECAFO · 1.6 mi
- BEYLA FARM, LLC (NEW CONSTRUCTION)CAFO · 1.8 mi
- EASTON FARM, LLCCAFO · 2.2 mi
- Former Skipjack EntUnderground Storage Tanks · 2.3 mi
- Royal Farms #135Underground Storage Tanks · 2.3 mi
- TOWN OF DENTONPFAS · 2.4 mi
- Behlke's Service CenterUnderground Storage Tanks · 2.4 mi
- CO Dd 49Nitrate · 2.4 mi
- George Wood EstateUnderground Storage Tanks · 2.5 mi
- Martinak State Park/DNR Forestry OfficeUnderground Storage Tanks · 2.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Williston'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 Williston.
Total Sites
502
within ~10 miles of Williston
Risk Level
Elevated
Highest-severity
3 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Williston
Severity Distribution
within ~10 miles of Williston
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Williston, two things run higher than the national average within ~10 miles of Williston — CAFO (116 sites) and Nitrate (222 sites). That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Williston
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 Williston average
Your land is one point inside Williston
Everything above resolves to Williston as a whole — one PHZM band and one 28°F frost record, read across 168 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 Williston Average
Williston Average
- ●USDA Zones 7b, averaged across Williston
- ●One soil character for all of Williston
- ●Frost dates read at Williston's scale: Mar 24 to Nov 16
YOUR Parcel
- ✓Your exact zone, not Williston's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Williston
Pull a site-specific report for your exact address in Williston, Maryland — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Williston averages can't show:
We read public map data around Williston — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Williston average
How we know this about Williston
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 Williston’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 Williston
When does frost risk typically end in Williston?
The last hard freeze (28°F) in Williston typically lands around Mar 24, 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 14.
When is the first frost in Williston?
The first hard freeze (28°F) in Williston typically arrives around Nov 16, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 2, so the watching starts about Oct 17 — about 237 days after the spring freeze cleared.
How long is the growing season in Williston?
Measured between 28°F hard freezes, Williston sees about 237 frost-free days — roughly Mar 24 through Nov 16, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 14 to Nov 2, about 202 days.
Is the soil safe to grow vegetables in Williston?
The federal record around Williston is a meaningful one — 502 documented sites, mostly Nitrate entries (222), the nearest Nitrate record about 0.2 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 Williston?
From about Oct 17 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 16 (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 16. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Williston's scale — its 7b band and its 237-day season. Your yard writes its own version of Williston'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 Williston’s own scale
7 of the readings below were taken at Williston's own scale — its own ~237-day season between 28°F freezes, the 168 acres it covers and 502 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Williston's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Williston's own 28°F hard-freeze dates, about Mar 24 and Nov 16 and the ~237-day span between themNOAA 1991–2020 Climate Normals
- 502 documented contamination sites on the federal record near Williston, the closest Nitrate record about 0.2 miles out from the town centreFederal environmental registers
- Williston's boundary and the 168 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~237-day seasonGrowable Ground crop-matching engine
- The ecoregion at Williston's own centroid, the Middle Atlantic Coastal PlainUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Willistonlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Williston's 168 acres read through its county's SSURGO summaryfrom Caroline County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Caroline 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 Caroline County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Williston's 168 acreswhy one lot differs from the next →
- Which side of Williston you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 168 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.2 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 Williston-wide figureread your own land →