Merrimac, 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.
Even in Merrimac, 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 Merrimac 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 Merrimac — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Merrimac — the short answer
Merrimac, Virginia: USDA zone 7a, about 210 days between hard freezes, across 1K 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)
- Oct 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~210
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 Merrimac's average, not your lot's — a low corner or a tree line moves it. Against Merrimac's 210-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Merrimac
Each reading below is measured for Merrimac itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMerrimac runs about 210 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
MeasuredMerrimac 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 Merrimac is in
Merrimac sits in the Ridge and Valley — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Merrimac's own centroid rather than borrowed from Montgomery County.
What Grows in Merrimac
Every plant below cleared Merrimac's own zone 7a and its 210-day season. Each card opens that plant's Virginia profile. How we score.
Is it too late to plant in Merrimac?
Usually not — gardeners here simply switch what goes in the ground as the season moves. 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 Oct 29 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
Documented around Merrimac
Spotted lanternfly documented 11 miles from Merrimac, first recorded 2022. What to watch for.
What's on the federal record near Merrimac
Closest first, within ~10 miles of Merrimac. Listing isn't leaking, and distance isn't exposure.
- Showalter CenterUnderground Storage Tanks · 1300 ft
- ENVIROTECH MID ATLANTICBrownfields · 0.7 mi
- SYNTHONS INCBrownfields · 0.7 mi
- C.L. DRAUGHN DITCHING CONTR INCUnderground Storage Tanks · 0.7 mi
- INTREXON CORPORATEBrownfields · 0.8 mi
- C.R. SULT INCUnderground Storage Tanks · 0.8 mi
- NANOSAFE MAIN OFFICEBrownfields · 0.9 mi
- UXB INTERNATIONAL, INC.Brownfields · 0.9 mi
- VTCRC COGRO LABSBrownfields · 0.9 mi
- REVIVICOR - XMLBrownfields · 0.9 mi
- REVIVICOR INCBrownfields · 0.9 mi
- STEWART'S TECHNOLOGIES, LLCBrownfields · 0.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Merrimac'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 Merrimac.
Total Sites
450
within ~10 miles of Merrimac
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Merrimac
Severity Distribution
within ~10 miles of Merrimac
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Merrimac, Underground Storage Tanks runs higher than the national average — 285 sites within ~10 miles of Merrimac. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Merrimac
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 Merrimac average
Your land is one point inside Merrimac
Everything above resolves to Merrimac as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Merrimac Average
Merrimac Average
- ●USDA Zones 7a, averaged across Merrimac
- ●One soil character for all of Merrimac
- ●Frost dates read at Merrimac's scale: Apr 2 to Oct 29
YOUR Parcel
- ✓Your exact zone, not Merrimac's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Merrimac
Pull a site-specific report for your exact address in Merrimac, Virginia — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Merrimac averages can't show:
We read public map data around Merrimac — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Merrimac average
How we know this about Merrimac
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 Merrimac’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 Merrimac
When does frost risk typically end in Merrimac?
The last hard freeze (28°F) in Merrimac 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 Merrimac?
The first hard freeze (28°F) in Merrimac typically arrives around Oct 29, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 15, so the watching starts about Sep 29 — about 210 days after the spring freeze cleared.
How long is the growing season in Merrimac?
Measured between 28°F hard freezes, Merrimac sees about 210 frost-free days — roughly Apr 2 through Oct 29, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 23 to Oct 15, about 175 days.
Is the soil safe to grow vegetables in Merrimac?
The federal record around Merrimac is a meaningful one — 450 documented sites, mostly Underground Storage Tanks entries (285), the nearest Underground Storage Tanks record about 0.2 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 Merrimac?
From about Sep 29 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 Oct 29 (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 Oct 29. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Merrimac's scale — its 7a band and its 210-day season. Your yard writes its own version of Merrimac'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 Merrimac’s own scale
7 of the readings below were taken at Merrimac's own scale — its own ~210-day season between 28°F freezes, the 1,100 acres it covers and 450 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Merrimac's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Merrimac's own 28°F hard-freeze dates, about Apr 2 and Oct 29 and the ~210-day span between themNOAA 1991–2020 Climate Normals
- 450 documented contamination sites on the federal record near Merrimac, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Merrimac's boundary and the 1,100 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~210-day seasonGrowable Ground crop-matching engine
- The ecoregion at Merrimac's own centroid, the Ridge and ValleyUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Merrimaclydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Merrimac's 1,100 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 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 Montgomery County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Merrimac's 1,100 acreswhy one lot differs from the next →
- Which side of Merrimac you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,100 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 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 Merrimac-wide figureread your own land →
More in Virginia
Growing region
Nearby growing guides