Gaithersburg, 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.
These conditions suit cabbage, prickly pear, california poppy, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Gaithersburg, 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 Gaithersburg 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 Gaithersburg — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Gaithersburg — the short answer
Gaithersburg, Maryland: USDA zone 7b, about 222 days between hard freezes, across 7K acres of city.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~222
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 7K 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 Gaithersburg's average, not your lot's — a low corner or a tree line moves it. Against Gaithersburg's 222-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Gaithersburg
Each reading below is measured for Gaithersburg itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredGaithersburg runs about 222 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
MeasuredGaithersburg 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 Gaithersburg is in
Gaithersburg sits in the Northern Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Gaithersburg's own centroid rather than borrowed from Montgomery County.
What Grows in Gaithersburg
Every plant below cleared Gaithersburg's own zone 7b and its 222-day season. Each card opens that plant's Maryland profile. How we score.
Is it too late to plant in Gaithersburg?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 30 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 7 — 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 Gaithersburg
Spotted lanternfly documented 3 miles from Gaithersburg, first recorded 2022. What to watch for.
What's on the federal record near Gaithersburg
Closest first, within ~10 miles of Gaithersburg. Listing isn't leaking, and distance isn't exposure.
- Asbury Methodist VillageUnderground Storage Tanks · 1100 ft
- Asbury Methodist Village (Wilson Health Care Center)Underground Storage Tanks · 1200 ft
- Kindley Assisted Living BuildingUnderground Storage Tanks · 1200 ft
- Giant Food Inc. Store #172Underground Storage Tanks · 1300 ft
- Asbury Methodist Village (Barn)Underground Storage Tanks · 1300 ft
- POTOMAC VALLEY CLEANERSBrownfields · 1300 ft
- DRI-VIN CLEANERSBrownfields · 1600 ft
- Edward-Fisher BuildingUnderground Storage Tanks · 1700 ft
- Montgomery Co. Outhouse RentalUnderground Storage Tanks · 1700 ft
- Mund Building - AMVUnderground Storage Tanks · 1700 ft
- Diamond BuildingUnderground Storage Tanks · 1800 ft
- Asbury Methodist Village (I.L. Building)Underground Storage Tanks · 1900 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Gaithersburg'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 Gaithersburg.
Total Sites
1,686
within ~10 miles of Gaithersburg
Risk Level
Elevated
Highest-severity
8 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Gaithersburg
Severity Distribution
within ~10 miles of Gaithersburg
Highest-Severity Sites
Know Before You Grow
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Gaithersburg
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 Gaithersburg average
Your land is one point inside Gaithersburg
Everything above resolves to Gaithersburg as a whole — one PHZM band and one 28°F frost record, read across 7K 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 city 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 Gaithersburg Average
Gaithersburg Average
- ●USDA Zones 7b, averaged across Gaithersburg
- ●One soil character for all of Gaithersburg
- ●Frost dates read at Gaithersburg's scale: Mar 30 to Nov 7
YOUR Parcel
- ✓Your exact zone, not Gaithersburg's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Gaithersburg
Pull a site-specific report for your exact address in Gaithersburg, Maryland — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Gaithersburg averages can't show:
We read public map data around Gaithersburg — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Gaithersburg average
How we know this about Gaithersburg
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Gaithersburg’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 city grain anywhere on this page — there is no city-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 Gaithersburg
When does frost risk typically end in Gaithersburg?
The last hard freeze (28°F) in Gaithersburg typically lands around Mar 30, 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 20.
When is the first frost in Gaithersburg?
The first hard freeze (28°F) in Gaithersburg typically arrives around Nov 7, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 24, so the watching starts about Oct 8 — about 222 days after the spring freeze cleared.
How long is the growing season in Gaithersburg?
Measured between 28°F hard freezes, Gaithersburg sees about 222 frost-free days — roughly Mar 30 through Nov 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 20 to Oct 24, about 187 days.
Is the soil safe to grow vegetables in Gaithersburg?
The federal record around Gaithersburg is a meaningful one — 1,686 documented sites, mostly Brownfields entries (789), the nearest Underground Storage Tanks 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 Gaithersburg?
From about Oct 8 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 7 (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 7. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Gaithersburg's scale — its 7b band and its 222-day season. Your yard writes its own version of Gaithersburg'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 Gaithersburg’s own scale
7 of the readings below were taken at Gaithersburg's own scale — its own ~222-day season between 28°F freezes, the 6,616 acres it covers and 1,686 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Gaithersburg's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Gaithersburg's own 28°F hard-freeze dates, about Mar 30 and Nov 7 and the ~222-day span between themNOAA 1991–2020 Climate Normals
- 1,686 documented contamination sites on the federal record near Gaithersburg, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Gaithersburg's boundary and the 6,616 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~222-day seasonGrowable Ground crop-matching engine
- The ecoregion at Gaithersburg's own centroid, the Northern PiedmontUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Gaithersburglydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Gaithersburg's 6,616 acres read through its county's SSURGO summaryfrom Montgomery County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Montgomery 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 Montgomery County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Gaithersburg's 6,616 acreswhy one lot differs from the next →
- Which side of Gaithersburg you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 6,616 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Gaithersburg-wide figureread your own land →