Washington Grove, 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.
Growers here do well with cabbage, prickly pear, california poppy, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Washington Grove, 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 Washington Grove 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 Washington Grove — soil, climate, flood, and parcel records. How we handle your address.
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Washington Grove — the short answer
Washington Grove, Maryland: USDA zone 7b, about 227 days between hard freezes, across 215 acres of town.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 11
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~227
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 215 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 Washington Grove's average, not your lot's — a low corner or a tree line moves it. Against Washington Grove's 227-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Washington Grove
Each reading below is measured for Washington Grove itself — here is what it means for a garden here, and the move an experienced grower makes about it.

Season length
MeasuredWashington Grove runs about 227 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
MeasuredWashington Grove 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 Washington Grove is in
Washington Grove sits in the Northern Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Washington Grove's own centroid rather than borrowed from Montgomery County.
What Grows in Washington Grove
Every plant below cleared Washington Grove's own zone 7b and its 227-day season. Each card opens that plant's Maryland profile. How we score.






























Is it too late to plant in Washington Grove?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 29 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 11 — 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 Washington Grove
Spotted lanternfly documented 3 miles from Washington Grove, first recorded 2018. What to watch for.
What's on the federal record near Washington Grove
Closest first, within ~10 miles of Washington Grove. Listing isn't leaking, and distance isn't exposure.
- SPIRENT COMMUNICATIONSToxics Release Inventory · 2100 ft
- ROBERTS OXYGEN CO INCBrownfields · 2200 ft
- Cable TV MontgomeryUnderground Storage Tanks · 2200 ft
- Roberts Oxygen Company, Inc.Underground Storage Tanks · 2200 ft
- WLK, LLCUnderground Storage Tanks · 0.5 mi
- Old Gaithersburg Depot SiteUnderground Storage Tanks · 0.5 mi
- Gaithersburg Highway DepotUnderground Storage Tanks · 0.5 mi
- WASHINGTON GROVE ELEMENTARY SCHOOLBrownfields · 0.6 mi
- HAN'S AUTO CENTERBrownfields · 0.6 mi
- Chesapeake Petroleum & Supply CompanyUnderground Storage Tanks · 0.6 mi
- United Pest ControlUnderground Storage Tanks · 0.7 mi
- PRINTING SERVICES INTL INCBrownfields · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Washington Grove'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 Washington Grove.
Total Sites
1,772
within ~10 miles of Washington Grove
Risk Level
Elevated
Highest-severity
8 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Washington Grove
Severity Distribution
within ~10 miles of Washington Grove
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 Washington Grove
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 Washington Grove average
Your land is one point inside Washington Grove
Everything above resolves to Washington Grove as a whole — one PHZM band and one 28°F frost record, read across 215 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 Washington Grove Average
Washington Grove Average
- ●USDA Zones 7b, averaged across Washington Grove
- ●One soil character for all of Washington Grove
- ●Frost dates read at Washington Grove's scale: Mar 29 to Nov 11
YOUR Parcel
- ✓Your exact zone, not Washington Grove's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Washington Grove
Pull a site-specific report for your exact address in Washington Grove, Maryland — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Washington Grove averages can't show:
We read public map data around Washington Grove — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Washington Grove average
How we know this about Washington Grove
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 Washington Grove’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 Washington Grove
When does frost risk typically end in Washington Grove?
The last hard freeze (28°F) in Washington Grove typically lands around Mar 29, 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 19.
When is the first frost in Washington Grove?
The first hard freeze (28°F) in Washington Grove typically arrives around Nov 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 28, so the watching starts about Oct 12 — about 227 days after the spring freeze cleared.
How long is the growing season in Washington Grove?
Measured between 28°F hard freezes, Washington Grove sees about 227 frost-free days — roughly Mar 29 through Nov 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 19 to Oct 28, about 192 days.
Is the soil safe to grow vegetables in Washington Grove?
The federal record around Washington Grove is a meaningful one — 1,772 documented sites, mostly Brownfields entries (836), the nearest Toxics Release Inventory record about 0.4 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 Washington Grove?
From about Oct 12 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 11 (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 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Washington Grove's scale — its 7b band and its 227-day season. Your yard writes its own version of Washington Grove'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 Washington Grove’s own scale
7 of the readings below were taken at Washington Grove's own scale — its own ~227-day season between 28°F freezes, the 215 acres it covers and 1,772 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Washington Grove's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Washington Grove's own 28°F hard-freeze dates, about Mar 29 and Nov 11 and the ~227-day span between themNOAA 1991–2020 Climate Normals
- 1,772 documented contamination sites on the federal record near Washington Grove, the closest Toxics Release Inventory record about 0.4 miles out from the town centreFederal environmental registers
- Washington Grove's boundary and the 215 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~227-day seasonGrowable Ground crop-matching engine
- The ecoregion at Washington Grove's own centroid, the Northern PiedmontUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Washington Grovelydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Washington Grove's 215 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 Washington Grove's 215 acreswhy one lot differs from the next →
- Which side of Washington Grove you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 215 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Toxics Release Inventory record about 0.4 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 Washington Grove-wide figureread your own land →
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