Loudoun County, in Virginia, sits in USDA hardiness zone 7a — a zone band wide enough that plant choice, not possibility, is the interesting question.
A short list that earns its place here — cabbage, hazelnut, california poppy, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Loudoun County lies within the Middleburg Virginia (Loudoun & Fauquier) — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Loudoun County holds more than one microclimate.
Soils and elevations shift across Loudoun County, so your frost dates and drainage aren't the county average. 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 Loudoun County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Loudoun County — the short answer
Loudoun County, Virginia: USDA zone 7a, about 218 days between hard freezes, across 330K acres.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 1
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 5
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~218
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 330K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 7a is Loudoun County's average, not your lot's — a low corner or a tree line moves it. Against Loudoun County's 218-day season, see what your own ground reads.
Heat in Loudoun County
Across a year, Loudoun County accumulates about 3,447 growing degree days above 50°F, about 287 fewer than the middle Virginia county — ahead of 39 of Virginia’s 133 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Loudoun County
Across Loudoun County, the ground is predominantly Alfisols, where Purcellville, Catoctin, and Tankerville are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 5.0–5.8, strongly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Alfisols
Drainage
Well drained
Prime farmland
33%
Hydric soils
7%
Soil still varies lot by lot — soil types explained.
How the ground varies across Loudoun County
The USDA soil survey maps 69% of Loudoun County as well drained — but another 28% drains differently: 14% somewhat poorly drained, 7% poorly drained.
Purcellville is the most extensive named soil at 16% of mapped acres, then Catoctin (8%) and Tankerville (7%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Loudoun County
Each reading below is measured for Loudoun County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Loudoun County are well drained, in hydrologic group B — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Loudoun County runs about pH 5.0–5.8, on the acidic side.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Season length
MeasuredLoudoun County runs about 218 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
MeasuredLoudoun County sits in USDA hardiness zone 7a.
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 Loudoun County is in
Loudoun County spans 2 EPA Level III ecoregions — Northern Piedmont (90%) and Blue Ridge (10%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Loudoun County
We scored all 1,086 plants against Loudoun County's own USDA zone 7a and its own 218-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Virginia profile.
Is it too late to plant in Loudoun County?
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 4; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 1 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 5 — 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 Loudoun County
Spotted lanternfly documented 1 miles from Loudoun County, first recorded 2021. What to watch for.
- Japanese beetle9 documented records
- monarch butterfly209 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Loudoun County
USGS estimates 48,201 lb of Glyphosate on Loudoun County farmland in 2019, its largest by weight, ahead of Atrazine (13,969 lb) and Simazine (7,338 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Loudoun County — and how to grow with it.
We checked the federal record across Loudoun County — 891 documented sites across 7 of the 9 source types we track.
The most significant on record: 2 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Loudoun County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Loudoun County
Closest first, across Loudoun County. Listing isn't leaking, and distance isn't exposure.
- BILL BURGESSUnderground Storage Tanks · 1.0 mi
- JOS CLEANERSBrownfields · 1.3 mi
- Piedmont Service CenterUnderground Storage Tanks · 1.8 mi
- THE BODY WORKS OF VIRGINIA INCORPORATEDBrownfields · 1.9 mi
- DR ROGERS RESIDENCEUnderground Storage Tanks · 2.7 mi
- Shadow Lake FarmsUnderground Storage Tanks · 3.0 mi
- WEST PARK HOTEL AND GOLFUnderground Storage Tanks · 3.5 mi
- LCPS - HERITAGE HSBrownfields · 3.6 mi
- LCPS - J. LUPTON SIMPSON MSBrownfields · 3.7 mi
- LCPS - EVERGREEN MILL ELEMENTARY SCHOOLBrownfields · 3.7 mi
- 50W 13BNitrate · 3.7 mi
- LOUDOUN COUNTY LANDFILLBrownfields · 3.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Loudoun County'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 Loudoun County.
Sources Checked
across Loudoun County
Severity Distribution
across Loudoun County
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.
- •TRI facilities report what they release. Check the wind — downwind beds catch more of it.
Check your specific parcel in Loudoun County
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 Loudoun County average
Your land is one point inside Loudoun County
Everything above resolves to Loudoun County as a whole — one PHZM band and one county frost record, read across 330K 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 county 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 county average.
Your Lot vs the Loudoun County Average
Loudoun County Average
- ●USDA Zones 7a, averaged across Loudoun County
- ●One soil character for all of Loudoun County
- ●Frost dates read at Loudoun County's scale: Apr 1 to Nov 5
YOUR Parcel
- ✓Your exact zone, not Loudoun County's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Loudoun County
Pull a site-specific report for your exact address in Loudoun County, Virginia — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Loudoun County averages can't show:
We read public map data around Loudoun County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Loudoun County average
How we know this about Loudoun County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Loudoun County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Loudoun County
When does frost risk typically end in Loudoun County?
The last hard freeze (28°F) in Loudoun County typically lands around Apr 1, 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 22.
How long is the growing season in Loudoun County?
Measured between 28°F hard freezes, Loudoun County sees about 218 frost-free days — roughly Apr 1 through Nov 5, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 22 to Oct 22, about 183 days.
Is the soil safe to grow vegetables in Loudoun County?
The federal record around Loudoun County is a meaningful one — 891 documented sites, mostly Brownfields entries (424), the nearest Underground Storage Tanks record about 1.0 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.
Everything above is measured at Loudoun County's scale — its 7a band and its 218-day season. Your yard writes its own version of Loudoun County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Virginia's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Loudoun County’s own scale
9 of the readings below were taken at Loudoun County's own scale — its own ~218-day span between 28°F freezes, the 3 most extensive soil series mapped here and 891 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Loudoun County's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Loudoun County's own 28°F hard-freeze dates and its ~218-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Loudoun CountyUSDA NRCS SSURGO
- 891 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 1.0 miles outFederal environmental registers
- Loudoun County's boundary and the 330,077 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~218-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Loudoun County spans, Northern Piedmont the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Loudoun County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Loudoun County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Virginia grower plans around — written at state scale, so they stay on the state guidefrom Virginia
What this page can’t tell you
- How the season shifts across Loudoun County — the ~218 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Loudoun County's 330,077 acreswhy one lot differs from the next →
- Which of those 891 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Loudoun Countyread your own land →