Fairfax County, in Virginia, sits in USDA hardiness zone 7b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
The conditions favor tomato, grape, peanut, and dogwood, among others — though every individual site edits that list with its own soil, sun, and drainage.
Fairfax County lies within the Piedmont — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Fairfax County holds more than one microclimate.
Soils and elevations shift across Fairfax County, so your frost dates and drainage aren't the county average. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Quick Facts
USDA Zones
7b
Last Hard Freeze (28°F)
Mar 8
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Dec 8
County normal — light frosts arrive a few weeks earlier
County Area
250K acres
Hardiness Zone Range
Zone maps are averages across Fairfax County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in Fairfax County
Across Fairfax County, the ground is predominantly Ultisols, where Glenelg, Wheaton, and Codorus are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 4.7–5.5, strongly acidic. Rainfall drains through hydrologic group C soils.
Soil order
Ultisols
Drainage
Well drained
Prime farmland
11%
Hydric soils
5%
Soil still varies lot by lot — soil types explained.
What Grows in Fairfax County
Plants matched to Fairfax County's USDA zones 7b — each links to its full growing profile.
Is it too late to plant in Fairfax County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 8 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 8 — long-season crops need about 90 days of runway, quick greens only 30. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.
Growing Challenges in Virginia
What an experienced grower plans around here — each one has a move.
Heavy Piedmont red clay requires amendment
Red clay turns from obstacle to asset with compost and time — and a raised bed lets you harvest while it happens.
Humidity and heat in summer promote disease
Space for airflow, water mornings at the base, and plant resistant varieties — your extension's humid-summer playbook.
Deer pressure is heavy in suburban and rural areas
A proper fence settles it; outside the fence, genuinely deer-resistant plants are the next best defense.
For cultivar selection, pest pressure, and planting-time guidance specific to Virginia, the Virginia Cooperative Extension is the authoritative local source.
Safe to Grow Here?
What the federal record shows across Fairfax County — and how to grow with it.
We checked the federal record across Fairfax County — 2,423 documented sites across 7 of the 9 source types we track.
The most significant on record: 8 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Fairfax County carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Sources Checked
across Fairfax County
Severity Distribution
across Fairfax County
Highest-Severity Sites
Know Before You Grow
- •Underground tanks can leak petroleum products. Soil testing near former gas stations is recommended.
- •Raised beds with imported soil can reduce exposure risk near brownfield sites.
- •TRI facilities report chemical releases. Check wind direction — downwind parcels face higher airborne exposure.
Check your specific parcel in Fairfax County
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Your Specific Parcel Matters
Fairfax County Average
- ●USDA Zones 7b
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Fairfax County
Pull a site-specific report for your exact address in Fairfax County, Virginia — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Key Growing Facts for Fairfax County, Virginia
- USDA Hardiness Zones: 7b (USDA PHZM 2023)
- Last Hard Freeze (28°F): Mar 8 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Dec 8 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~275 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 250K acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. County boundaries: US Census TIGER/Line 2025.
Frost dates here are the Fairfax County average. Low spots and tree cover move them by days on any one yard — see your exact frost windows.
Frequently Asked Questions
What hardiness zone is Fairfax County, Virginia?
Fairfax County sits in USDA hardiness zone 7b, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
Is it too late to plant in Fairfax County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 8 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 8 — long-season crops need about 90 days of runway, quick greens only 30. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.
When does frost risk typically end in Fairfax County?
The last hard freeze (28°F) in Fairfax County typically lands around Mar 8, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.
How long is the growing season in Fairfax County?
Measured between 28°F hard freezes, Fairfax County sees about 275 frost-free days — roughly Mar 8 through Dec 8, per NOAA 1991–2020 climate normals. Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
What vegetables grow in Fairfax County?
Fairfax County's zone 7b supports a wide range — strong performers include Tomato, Grape, Peanut, Dogwood, and Apple. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Which hardiness zone is Fairfax County, really?
Officially, Fairfax County sits in USDA zone 7b (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,112 plants against what's actually there.
Is the soil safe to grow vegetables in Fairfax County?
The federal record around Fairfax County runs heavier than most — 2,423 documented sites — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Just moved to Fairfax County — what should I know before planting?
Start with three facts. Fairfax County sits in USDA zone 7b, which sets what survives winter; the last 28°F hard freeze typically clears around Mar 8, with about 275 frost-free days to work with (NOAA 1991–2020 climate normals); and 2,423 documented sites sit on the federal record here, so a soil test before food beds is the smart first step. From there, matching plants to your actual soil and sun is the fun part.
Everything on this page is a Fairfax County average. Your yard writes its own version — 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.