Harrington, Delaware, sits in USDA hardiness zone 7b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Well-matched crops include cabbage, prickly pear, california poppy, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Harrington, 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 Harrington 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 Harrington — soil, climate, flood, and parcel records. How we handle your address.
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Harrington — the short answer
Harrington, Delaware: USDA zone 7b, about 232 days between hard freezes, across 2K acres of city.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 25
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~232
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 2K 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 7b is Harrington's average, not your lot's — a low corner or a tree line moves it. Against Harrington's 232-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Harrington
Each reading below is measured for Harrington itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHarrington runs about 232 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
MeasuredHarrington 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 Harrington is in
Harrington sits in the Middle Atlantic Coastal Plain — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Harrington's own centroid rather than borrowed from Kent County.
What Grows in Harrington
Every plant below cleared Harrington's own zone 7b and its 232-day season. Each card opens that plant's Delaware profile. How we score.
Is it too late to plant in Harrington?
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 Feb 25; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 25 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 12 — 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 Harrington
Spotted lanternfly documented 2 miles from Harrington, first recorded 2020. What to watch for.
What's on the federal record near Harrington
Closest first, within ~10 miles of Harrington. Listing isn't leaking, and distance isn't exposure.
- Delmarva Power & Light Co HarringtonUnderground Storage Tanks · 550 ft
- Charles Corbit ArmoryUnderground Storage Tanks · 550 ft
- FAMILY DOLLAR STORES OF DE, LLC. #1162Brownfields · 900 ft
- Harrington Tru BluUnderground Storage Tanks · 950 ft
- Higrade DairyUnderground Storage Tanks · 950 ft
- Peoples Service Oil or RestaurantUnderground Storage Tanks · 950 ft
- Lift Parts & ServiceUnderground Storage Tanks · 1000 ft
- Ken Meredith & SonUnderground Storage Tanks · 1200 ft
- Shore Stop #272 HarringtonUnderground Storage Tanks · 1300 ft
- Kemps Frozen FoodsUnderground Storage Tanks · 1400 ft
- IA Construction CorpUnderground Storage Tanks · 1400 ft
- Towers Auto ServiceUnderground Storage Tanks · 1400 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Harrington'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 Harrington.
Total Sites
436
within ~10 miles of Harrington
Risk Level
Elevated
Highest-severity
4 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Harrington
Severity Distribution
within ~10 miles of Harrington
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Harrington, CAFO runs higher than the national average — 9 sites within ~10 miles of Harrington. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check your specific parcel in Harrington
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 Harrington average
Your land is one point inside Harrington
Everything above resolves to Harrington as a whole — one PHZM band and one 28°F frost record, read across 2K 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 city 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 Harrington Average
Harrington Average
- ●USDA Zones 7b, averaged across Harrington
- ●One soil character for all of Harrington
- ●Frost dates read at Harrington's scale: Mar 25 to Nov 12
YOUR Parcel
- ✓Your exact zone, not Harrington's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Harrington
Pull a site-specific report for your exact address in Harrington, Delaware — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Harrington averages can't show:
We read public map data around Harrington — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Harrington average
How we know this about Harrington
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Harrington’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 city grain anywhere on this page — there is no city-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 Harrington
When does frost risk typically end in Harrington?
The last hard freeze (28°F) in Harrington typically lands around Mar 25, 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 15.
When is the first frost in Harrington?
The first hard freeze (28°F) in Harrington typically arrives around Nov 12, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 29, so the watching starts about Oct 13 — about 232 days after the spring freeze cleared.
How long is the growing season in Harrington?
Measured between 28°F hard freezes, Harrington sees about 232 frost-free days — roughly Mar 25 through Nov 12, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 15 to Oct 29, about 197 days.
Is the soil safe to grow vegetables in Harrington?
The federal record around Harrington is a meaningful one — 436 documented sites, mostly Underground Storage Tanks entries (249), the nearest Underground Storage Tanks record about 0.1 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 Harrington?
From about Oct 13 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 12 (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 12. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Harrington's scale — its 7b band and its 232-day season. Your yard writes its own version of Harrington'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 Harrington’s own scale
7 of the readings below were taken at Harrington's own scale — its own ~232-day season between 28°F freezes, the 1,743 acres it covers and 436 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Harrington's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Harrington's own 28°F hard-freeze dates, about Mar 25 and Nov 12 and the ~232-day span between themNOAA 1991–2020 Climate Normals
- 436 documented contamination sites on the federal record near Harrington, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Harrington's boundary and the 1,743 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~232-day seasonGrowable Ground crop-matching engine
- The ecoregion at Harrington's own centroid, the Middle Atlantic Coastal PlainUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Harringtonlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Harrington's 1,743 acres read through its county's SSURGO summaryfrom Kent County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Kent County
- The growing challenges every Delaware grower plans around — written at state scale, so they stay on the state guidefrom Delaware
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Kent County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Harrington's 1,743 acreswhy one lot differs from the next →
- Which side of Harrington you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,743 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Harrington-wide figureread your own land →