Round Hill, Virginia, sits in USDA hardiness zone 7a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
These conditions suit cabbage, hazelnut, california poppy, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Round Hill, 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 Round Hill 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 Round Hill — soil, climate, flood, and parcel records. How we handle your address.
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Round Hill — the short answer
Round Hill, Virginia: USDA zone 7a, about 213 days between hard freezes, across 235 acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 1
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~213
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 235 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 7a is Round Hill's average, not your lot's — a low corner or a tree line moves it. Against Round Hill's 213-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Round Hill
Each reading below is measured for Round Hill itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredRound Hill runs about 213 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
MeasuredRound Hill 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 Round Hill is in
Round Hill sits in the Northern Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Round Hill's own centroid rather than borrowed from Loudoun County.
What Grows in Round Hill
Every plant below cleared Round Hill's own zone 7a and its 213-day season. Each card opens that plant's Virginia profile. How we score.
Is it too late to plant in Round Hill?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Mar 5; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 2 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 1 — 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 Round Hill
Spotted lanternfly documented 2 miles from Round Hill, first recorded 2022. What to watch for.
What's on the federal record near Round Hill
Closest first, within ~10 miles of Round Hill. Listing isn't leaking, and distance isn't exposure.
- HARPERS GAS STATIONUnderground Storage Tanks · 500 ft
- Round Hill ExxonUnderground Storage Tanks · 550 ft
- ROUND HILL TEXACOUnderground Storage Tanks · 650 ft
- ROUND HILL FIRE STATION/SHERIFFS SUBSTATIONUnderground Storage Tanks · 800 ft
- RICHARD P CARTER BUILDER INCUnderground Storage Tanks · 1300 ft
- BAYLESS PROPERTYUnderground Storage Tanks · 1300 ft
- LCPS - ROUND HILL CENTERBrownfields · 2000 ft
- LCPS - ROUND HILL ELEMENTARY SCHOOLBrownfields · 1.0 mi
- FRANKLIN FARMS PARKUnderground Storage Tanks · 1.3 mi
- 48X 19Nitrate · 2.2 mi
- ROBERT J SCHONDERUnderground Storage Tanks · 2.3 mi
- LOUDOUN MILK TRANSPORTAION, INCUnderground Storage Tanks · 2.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Round Hill'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 Round Hill.
Total Sites
253
within ~10 miles of Round Hill
Risk Level
Elevated
Highest-severity
3 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Round Hill
Severity Distribution
within ~10 miles of Round Hill
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Round Hill, Nitrate runs higher than the national average — 110 sites within ~10 miles of Round Hill. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Round Hill
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 Round Hill average
Your land is one point inside Round Hill
Everything above resolves to Round Hill as a whole — one PHZM band and one 28°F frost record, read across 235 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 Round Hill Average
Round Hill Average
- ●USDA Zones 7a, averaged across Round Hill
- ●One soil character for all of Round Hill
- ●Frost dates read at Round Hill's scale: Apr 2 to Nov 1
YOUR Parcel
- ✓Your exact zone, not Round Hill's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Round Hill
Pull a site-specific report for your exact address in Round Hill, Virginia — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Round Hill averages can't show:
We read public map data around Round Hill — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Round Hill average
How we know this about Round Hill
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 Round Hill’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 Round Hill
When does frost risk typically end in Round Hill?
The last hard freeze (28°F) in Round Hill typically lands around Apr 2, 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 23.
When is the first frost in Round Hill?
The first hard freeze (28°F) in Round Hill typically arrives around Nov 1, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 18, so the watching starts about Oct 2 — about 213 days after the spring freeze cleared.
How long is the growing season in Round Hill?
Measured between 28°F hard freezes, Round Hill sees about 213 frost-free days — roughly Apr 2 through Nov 1, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 23 to Oct 18, about 178 days.
Is the soil safe to grow vegetables in Round Hill?
The federal record around Round Hill is a meaningful one — 253 documented sites, mostly Nitrate entries (110), the nearest Underground Storage Tanks record under a tenth of a mile 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 Round Hill?
From about Oct 2 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 1 (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 1. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Round Hill's scale — its 7a band and its 213-day season. Your yard writes its own version of Round Hill'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 Round Hill’s own scale
7 of the readings below were taken at Round Hill's own scale — its own ~213-day season between 28°F freezes, the 235 acres it covers and 253 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Round Hill's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Round Hill's own 28°F hard-freeze dates, about Apr 2 and Nov 1 and the ~213-day span between themNOAA 1991–2020 Climate Normals
- 253 documented contamination sites on the federal record near Round Hill, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Round Hill's boundary and the 235 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~213-day seasonGrowable Ground crop-matching engine
- The ecoregion at Round Hill's own centroid, the Northern PiedmontUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Round Hilllydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Round Hill's 235 acres read through its county's SSURGO summaryfrom Loudoun County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Loudoun County
- The growing challenges every Virginia grower plans around — written at state scale, so they stay on the state guidefrom Virginia
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Loudoun County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Round Hill's 235 acreswhy one lot differs from the next →
- Which side of Round Hill you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 235 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Round Hill-wide figureread your own land →