Harford County, in Maryland, sits in USDA hardiness zone 7b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Reliable performers under these conditions include cabbage, prickly pear, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Harford County lies within the Maryland Piedmont — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Harford County holds more than one microclimate.
Soils and elevations shift across Harford 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 Harford County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Harford County — the short answer
Harford County, Maryland: USDA zone 7b, about 227 days between hard freezes, across 280K acres.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 29
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 11
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~227
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 280K 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 7b is Harford County's average, not your lot's — a low corner or a tree line moves it. Against Harford County's 227-day season, see what your own ground reads.
Heat in Harford County
Across a year, Harford County accumulates about 3,607 growing degree days above 50°F, about 257 fewer than the middle Maryland county — ahead of 7 of Maryland’s 24 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 Harford County
Across Harford County, the ground is predominantly Ultisols, where Glenelg, Manor, and Chester are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 5.0–5.5, strongly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Ultisols
Drainage
Well drained
Prime farmland
33%
Hydric soils
10%
Soil still varies lot by lot — soil types explained.
How the ground varies across Harford County
The USDA soil survey maps 59% of Harford County as well drained — but another 29% drains differently: 16% moderately well drained, 7% poorly drained.
Glenelg is the most extensive named soil at 18% of mapped acres, then Manor (15%) and Chester (14%).
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 Harford County
Each reading below is measured for Harford 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 Harford 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 Harford County runs about pH 5.0–5.5, 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
MeasuredHarford County 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
MeasuredHarford County 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 Harford County is in
Harford County spans 3 EPA Level III ecoregions — Northern Piedmont (76%), Middle Atlantic Coastal Plain (17%) and Southeastern Plains (7%). 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 Harford County
We scored all 1,086 plants against Harford County's own USDA zone 7b and its own 227-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 Maryland profile.
Is it too late to plant in Harford County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. 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. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
Documented around Harford County
Spotted lanternfly documented 3 miles from Harford County, first recorded 2019. What to watch for.
- Japanese beetle2 documented records
- monarch butterfly19 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Harford County
USGS estimates 69,751 lb of Glyphosate on Harford County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (29,536 lb) and Metolachlor-s (28,495 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 Harford County — and how to grow with it.
We checked the federal record across Harford County — 1,421 documented sites across 8 of the 9 source types we track.
The most significant on record: 11 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Harford 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.
What's on the federal record near Harford County
Closest first, across Harford County. Listing isn't leaking, and distance isn't exposure.
- Bel Air Service CenterUnderground Storage Tanks · 1800 ft
- Mary M. StephenUnderground Storage Tanks · 2300 ft
- HA Cd 201Nitrate · 0.5 mi
- HA Cd 188Nitrate · 0.7 mi
- Former Royal Farms #25Underground Storage Tanks · 0.9 mi
- Royal Farms #25Underground Storage Tanks · 1.0 mi
- WALGREENS #17619Brownfields · 1.0 mi
- Fountain Green GulfUnderground Storage Tanks · 1.0 mi
- Wawa Food Market #557Underground Storage Tanks · 1.0 mi
- Francis Construction Co., Inc.Underground Storage Tanks · 1.1 mi
- ADVANCE AUTO PARTS # 8767Brownfields · 1.2 mi
- AMYCLAE CLEANERSBrownfields · 1.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Harford 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 Harford County.
Severity Distribution
across Harford County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Harford County, Nitrate runs higher than the national average — 384 sites across Harford County. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Harford 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 Harford County average
Your land is one point inside Harford County
Everything above resolves to Harford County as a whole — one PHZM band and one county frost record, read across 280K 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 Harford County Average
Harford County Average
- ●USDA Zones 7b, averaged across Harford County
- ●One soil character for all of Harford County
- ●Frost dates read at Harford County's scale: Mar 29 to Nov 11
YOUR Parcel
- ✓Your exact zone, not Harford County's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Harford County
Pull a site-specific report for your exact address in Harford County, Maryland — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Harford County averages can't show:
We read public map data around Harford County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Harford County average
How we know this about Harford 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 Harford County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Harford County
When does frost risk typically end in Harford County?
The last hard freeze (28°F) in Harford County 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.
How long is the growing season in Harford County?
Measured between 28°F hard freezes, Harford County 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 Harford County?
The federal record around Harford County runs heavier than most — 1,421 documented sites, mostly Underground Storage Tanks entries (559), the nearest Underground Storage Tanks record about 0.3 miles out — 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.
Everything above is measured at Harford County's scale — its 7b band and its 227-day season. Your yard writes its own version of Harford 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 Maryland's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Harford County’s own scale
9 of the readings below were taken at Harford County's own scale — its own ~227-day span between 28°F freezes, the 3 most extensive soil series mapped here and 1,421 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Harford County's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Harford County's own 28°F hard-freeze dates and its ~227-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Harford CountyUSDA NRCS SSURGO
- 1,421 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 0.3 miles outFederal environmental registers
- Harford County's boundary and the 279,760 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 3 ecoregions Harford County spans, Northern Piedmont the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Harford County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Harford County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Maryland grower plans around — written at state scale, so they stay on the state guidefrom Maryland
What this page can’t tell you
- How the season shifts across Harford County — the ~227 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 Harford County's 279,760 acreswhy one lot differs from the next →
- Which of those 1,421 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 Harford Countyread your own land →