Port Penn, Delaware, 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.
Even in Port Penn, 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 Port Penn 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 Port Penn — soil, climate, flood, and parcel records. How we handle your address.
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Port Penn — the short answer
Port Penn, Delaware: USDA zone 7b, about 240 days between hard freezes, across 259 acres of town.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 18
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~240
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 259 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 Port Penn's average, not your lot's — a low corner or a tree line moves it. Against Port Penn's 240-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Port Penn
Each reading below is measured for Port Penn itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredPort Penn runs about 240 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
MeasuredPort Penn 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 Port Penn is in
Port Penn sits in the Middle Atlantic Coastal Plain — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Port Penn's own centroid rather than borrowed from New Castle County.
What Grows in Port Penn
Every plant below cleared Port Penn's own zone 7b and its 240-day season. Each card opens that plant's Delaware profile. How we score.
Is it too late to plant in Port Penn?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Feb 23; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 18 — 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 Port Penn
Spotted lanternfly documented 4 miles from Port Penn, first recorded 2019. What to watch for.
What's on the federal record near Port Penn
Closest first, within ~10 miles of Port Penn. Listing isn't leaking, and distance isn't exposure.
- Ed51-10Nitrate · 750 ft
- Port Penn Fire CompanyUnderground Storage Tanks · 1200 ft
- Augustine Wildlife AreaUnderground Storage Tanks · 1500 ft
- PCMN-153Nitrate · 1.5 mi
- Fc14-06Nitrate · 2.3 mi
- Ec43-08Nitrate · 2.4 mi
- Ec53-05Nitrate · 2.5 mi
- Ec43-09Nitrate · 2.5 mi
- Ec33-01Nitrate · 2.5 mi
- Ec33-02Nitrate · 2.6 mi
- Ed21-20Nitrate · 2.7 mi
- Ec43-07Nitrate · 2.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Port Penn'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 Port Penn.
Sources Checked
within ~10 miles of Port Penn
Severity Distribution
within ~10 miles of Port Penn
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Port Penn, two things run higher than the national average within ~10 miles of Port Penn — Nitrate (338 sites) and Superfund (13 sites). 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.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Port Penn
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 Port Penn average
Your land is one point inside Port Penn
Everything above resolves to Port Penn as a whole — one PHZM band and one 28°F frost record, read across 259 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 Port Penn Average
Port Penn Average
- ●USDA Zones 7b, averaged across Port Penn
- ●One soil character for all of Port Penn
- ●Frost dates read at Port Penn's scale: Mar 23 to Nov 18
YOUR Parcel
- ✓Your exact zone, not Port Penn's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Port Penn
Pull a site-specific report for your exact address in Port Penn, Delaware — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Port Penn averages can't show:
We read public map data around Port Penn — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Port Penn average
How we know this about Port Penn
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 Port Penn’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 Port Penn
When does frost risk typically end in Port Penn?
The last hard freeze (28°F) in Port Penn typically lands around Mar 23, 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 13.
When is the first frost in Port Penn?
The first hard freeze (28°F) in Port Penn typically arrives around Nov 18, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 4, so the watching starts about Oct 19 — about 240 days after the spring freeze cleared.
How long is the growing season in Port Penn?
Measured between 28°F hard freezes, Port Penn sees about 240 frost-free days — roughly Mar 23 through Nov 18, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 13 to Nov 4, about 205 days.
Is the soil safe to grow vegetables in Port Penn?
The federal record around Port Penn runs heavier than most — 803 documented sites, mostly Nitrate entries (338), the nearest Nitrate record about 0.1 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.
How do I protect my plants from frost in Port Penn?
From about Oct 19 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 18 (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 18. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Port Penn's scale — its 7b band and its 240-day season. Your yard writes its own version of Port Penn'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 Port Penn’s own scale
7 of the readings below were taken at Port Penn's own scale — its own ~240-day season between 28°F freezes, the 259 acres it covers and 803 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Port Penn's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Port Penn's own 28°F hard-freeze dates, about Mar 23 and Nov 18 and the ~240-day span between themNOAA 1991–2020 Climate Normals
- 803 documented contamination sites on the federal record near Port Penn, the closest Nitrate record about 0.1 miles out from the town centreFederal environmental registers
- Port Penn's boundary and the 259 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~240-day seasonGrowable Ground crop-matching engine
- The ecoregion at Port Penn's own centroid, the Middle Atlantic Coastal PlainUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Port Pennlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Port Penn's 259 acres read through its county's SSURGO summaryfrom New Castle County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom New Castle 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 New Castle County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Port Penn's 259 acreswhy one lot differs from the next →
- Which side of Port Penn you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 259 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate 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 Port Penn-wide figureread your own land →