Cabin John, 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.
Expect cabbage, prickly pear, california poppy, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Cabin John, 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 Cabin John 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 Cabin John — soil, climate, flood, and parcel records. How we handle your address.
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Cabin John — the short answer
Cabin John, Maryland: USDA zone 7b, about 245 days between hard freezes, across 781 acres of town.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~245
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 781 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 Cabin John's average, not your lot's — a low corner or a tree line moves it. Against Cabin John's 245-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Cabin John
Each reading below is measured for Cabin John itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCabin John runs about 245 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
MeasuredCabin John 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 Cabin John is in
Cabin John sits in the Northern Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Cabin John's own centroid rather than borrowed from Montgomery County.
What Grows in Cabin John
Every plant below cleared Cabin John's own zone 7b and its 245-day season. Each card opens that plant's Maryland profile. How we score.
Is it too late to plant in Cabin John?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Feb 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 20 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 20 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
Documented around Cabin John
Spotted lanternfly documented 2 miles from Cabin John, first recorded 2022. What to watch for.
What's on the federal record near Cabin John
Closest first, within ~10 miles of Cabin John. Listing isn't leaking, and distance isn't exposure.
- MDOT SHA BRIDGE #1510400Brownfields · 1600 ft
- WSSC- CABIN JOHN ELEVATED TANKBrownfields · 1800 ft
- SHA BRIDGE #1514200Brownfields · 0.5 mi
- MDOT SHA BRIDGE #1510100Brownfields · 0.5 mi
- SHA BRIDGE 1508700Brownfields · 0.8 mi
- SHA BRIDGE 1508600Brownfields · 0.8 mi
- LANGLEY OAKS PUMPING STATIONUnderground Storage Tanks · 1.1 mi
- Tri State Stone & Building Supply, Inc.Underground Storage Tanks · 1.1 mi
- TURKEY RUN PARK-HQUnderground Storage Tanks · 1.2 mi
- MO Fe 12Nitrate · 1.3 mi
- Glen Echo ParkUnderground Storage Tanks · 1.3 mi
- NATIONAL PARK SERVICEBrownfields · 1.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Cabin John'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 Cabin John.
Total Sites
4,590
within ~10 miles of Cabin John
Risk Level
Elevated
Highest-severity
41 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Cabin John
Severity Distribution
within ~10 miles of Cabin John
Highest-Severity Sites
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.
Check your specific parcel in Cabin John
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 Cabin John average
Your land is one point inside Cabin John
Everything above resolves to Cabin John as a whole — one PHZM band and one 28°F frost record, read across 781 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 Cabin John Average
Cabin John Average
- ●USDA Zones 7b, averaged across Cabin John
- ●One soil character for all of Cabin John
- ●Frost dates read at Cabin John's scale: Mar 20 to Nov 20
YOUR Parcel
- ✓Your exact zone, not Cabin John's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Cabin John
Pull a site-specific report for your exact address in Cabin John, Maryland — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Cabin John averages can't show:
We read public map data around Cabin John — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Cabin John average
How we know this about Cabin John
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 Cabin John’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 Cabin John
When does frost risk typically end in Cabin John?
The last hard freeze (28°F) in Cabin John typically lands around Mar 20, 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 10.
When is the first frost in Cabin John?
The first hard freeze (28°F) in Cabin John typically arrives around Nov 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 6, so the watching starts about Oct 21 — about 245 days after the spring freeze cleared.
How long is the growing season in Cabin John?
Measured between 28°F hard freezes, Cabin John sees about 245 frost-free days — roughly Mar 20 through Nov 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 10 to Nov 6, about 210 days.
Is the soil safe to grow vegetables in Cabin John?
The federal record around Cabin John is a meaningful one — 4,590 documented sites, mostly Underground Storage Tanks entries (2,379), the nearest Brownfields 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 Cabin John?
From about Oct 21 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 20 (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 20. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Cabin John's scale — its 7b band and its 245-day season. Your yard writes its own version of Cabin John'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 Cabin John’s own scale
7 of the readings below were taken at Cabin John's own scale — its own ~245-day season between 28°F freezes, the 781 acres it covers and 4,590 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Cabin John's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Cabin John's own 28°F hard-freeze dates, about Mar 20 and Nov 20 and the ~245-day span between themNOAA 1991–2020 Climate Normals
- 4,590 documented contamination sites on the federal record near Cabin John, the closest Brownfields record about 0.3 miles out from the town centreFederal environmental registers
- Cabin John's boundary and the 781 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~245-day seasonGrowable Ground crop-matching engine
- The ecoregion at Cabin John's own centroid, the Northern PiedmontUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Cabin Johnlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Cabin John's 781 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 Cabin John's 781 acreswhy one lot differs from the next →
- Which side of Cabin John you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 781 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Cabin John-wide figureread your own land →
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