Delaware spans USDA hardiness zones 7a-8a, with a growing season of about 241 frost-free days — a season with slack in it: successions, late sowings, and long-maturing crops all fit.
Taken together, 42-48 inches of annual rainfall, a median of roughly 3,732 growing-degree days (base 50°F), and about 2,500 winter chill hours for tree fruit draw the line between what thrives here and what merely survives. Dig almost anywhere and you'll meet sandy loam, silt loam, and tidal marsh; how quickly they shed water is the first thing to learn about them. No single calendar covers Delaware: Tidewater & Chesapeake, Delmarva Peninsula, and Brandywine Valley each open and close their seasons on their own schedule. Crops well matched to these conditions include tomato, sweet corn, peach, and blueberry — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Grounded inUSDA PHZM•NOAA Climate Normals•USDA NRCS SSURGO•GDD (PRISM 1991-2020 normals)•Chill hours (PRISM 1991-2020 normals)•USDA hardiness sub-region map•EPA FRS•USDA PLANTS•Growable Ground suitability scoring
Delaware spans zones 7a-8a, but your yard sits in exactly one — and slope, tree cover, and low spots nudge it further. 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 Delaware — soil, climate, flood, and parcel records. How we handle your address.
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Distinct growing regions within Delaware — each has its own zones, soils, and signature crops.
Delaware: USDA zones 7a-8a, about 241 frost-free days in a typical county, 3 counties.
The middle half of this state’s counties. Tender transplants usually wait 2–3 weeks past the last hard freeze.
Delaware does not have one growing season. Across all 75 of its towns that carry their own 30-year record, the shortest measured season is North Star's at 224 days and the longest is Lewes's at 267 — a 43-day spread inside one state.
Neither end is a lone reading — another 19 towns measure within 10 days of North Star and 6 sit within 10 days of Lewes. These are real pockets, so the number to plant against is your own town's, not the state average.
NOAA Regional Climate Centers ACIS (1991–2020), 30-year daily minimum record
Zone 7a-8a is Delaware's average, not your lot's — a low corner or a tree line moves it. Against Delaware's 241-day season, see what your own ground reads.
The soil types that dominate Delaware — how each drains decides more about crop success than almost anything else. Tap any soil to learn what it is and how to work with it. Each photo is a representative profile of that soil type; the named series is where it was documented, which is often another state.
Drainage
Fast. The sand fraction opens the soil up, so water moves through the root zone quickly and the surface rarely stays soggy. The trade is that nutrients ride out with the water.
What thrives
Root crops love it — carrots, potatoes, radishes, and onions size up cleanly in ground they can push through. Melons, sweet potatoes, asparagus, and most herbs appreciate the warmth and the drainage.
Drainage
Moderate. Silt holds water well and releases it steadily, though the fine particles can crust after hard rain and compact under traffic.
What thrives
The full vegetable garden does well here, and small grains, corn, and leafy greens are classic silt-loam crops. Its steady moisture suits shallow-rooted plants that dislike drought stress.
Drainage
Tide-ruled: saturated on the flood, briefly drained on the ebb. Conventional beds are not what this ground is for.
What thrives
Salt-marsh natives — cordgrass, sea lavender, marsh elder — and the wildlife economy they support. Upland edges above the tide line grow salt-tolerant shrubs and gardens in raised, protected beds.
Soil data: USDA NRCS SSURGO · Soil types explained
Plants well-suited to Delaware's climate, soils, and growing season — each links to its full growing profile.
Rarely: the season closes in stages, not all at once, and each stage has its crops. Across Delaware, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Mar 23, with the middle half of counties between Mar 23 and Mar 23 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Nov 17 and Nov 19 — 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.
The plants Delaware put its name on — cultural emblems, not growing recommendations.
Prunus persica
Designated 1953. In our plant library — see its full growing profile.
Ilex opaca
Designated 1939. In our plant library — see its full growing profile.
Plants the USDA PLANTS Database documents as native and present in Delaware — a real per-state range, not just a zone match. Ordered by how closely each plant’s published hardiness range matches Delaware’s zones 7a-8a, so this is a shortlist by climate fit, not a ranking of which plants matter most here. Presence is statewide, so a plant may still be uncommon in your specific county; your state’s Cooperative Extension or a native-plant society is the local authority.
US-native plants whose hardiness range overlaps Delaware’s USDA zones 7a-8a but which USDA PLANTS doesn’t map to a single state range here. Zone overlap is a starting filter, not a range map.
What an experienced grower plans around here — each one has a move.
Sandy soils in southern DE drain too quickly
Organic matter is the fix, applied annually — compost and cover crops teach sandy ground to hold water and nutrients.
Salt spray damage near the coast
Salt-tolerant species up front and a windbreak line behind — a layered coastal defense that catches the spray.
Rising water tables in low-lying areas
Where the water table rises, grow up: mounded rows and raised beds keep roots out of saturated ground.
For cultivar selection, pest pressure, and planting-time guidance specific to Delaware, the University of Delaware Cooperative Extension is the authoritative local source.
Safe to Grow Here?What the federal record shows across Delaware — and how to grow with it.
We checked the federal record across Delaware — 6,167 documented sites across 8 of the 9 source types we track.
The most significant on record: 64 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Delaware 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.
Severity Distribution
across Delaware
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Delaware, Nitrate runs higher than the national average — 1,646 sites across Delaware. That's not a problem with your land — it's information about it.
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).
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Everything above resolves to Delaware as a whole — a footprint spanning USDA zones 7a-8a. Your parcel sits in exactly one of them. 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 state 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 statewide average.
State averages sketch the shape. Your soil, sun exposure, drainage, and microclimate decide what actually takes. Pull a site-specific report for your exact parcel.
Enter your address. We read your soil, sun, drainage, and frost dates, then score 1,086 plants against the real conditions on your land.
Three things about your lot that Delaware averages can't show:
We read public map data around Delaware — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Delaware average
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read per county and aggregated to the state band; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each county’s own record; rainfall from NOAA Climate Normals; soils from USDA NRCS SSURGO; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above. Where a county carries no record of its own, it is absent from the figure rather than filled in.
Delaware spans USDA hardiness zones 7a-8a — which is to say winter's coldest night runs from about 0°F to 15°F depending where in Delaware you are, averaged over 1991–2020 (USDA PHZM 2023).
Rarely: the season closes in stages, not all at once, and each stage has its crops. Across Delaware, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Mar 23, with the middle half of counties between Mar 23 and Mar 23 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Nov 17 and Nov 19 — 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.
Across Delaware, the middle half of counties see their last hard freeze (28°F) between about Mar 23 and Mar 23, with a county median near Mar 23 (NOAA 1991–2020 climate normals). 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.
Measured between 28°F hard freezes, growing seasons across Delaware's counties mostly run about 240 to 241 days, with a county median near 241 (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.
Delaware's zones 7a-8a support a wide range — strong performers include Tomato, Sweet Corn, Peach, Blueberry, and Holly. 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.
Officially, Delaware spans USDA zones 7a-8a (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 1,086 plants against what's actually there.
The federal record across Delaware runs heavier than most — 6,167 documented sites, mostly Underground Storage Tanks entries (2,917) — 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.
Start with three facts. Delaware spans USDA zones 7a-8a, which sets what survives winter; last hard freezes range from about Mar 23 to Mar 23 across its counties (NOAA 1991–2020 climate normals); and 6,167 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 above is measured at Delaware's scale — its 7a-8a band and its 241-day season. Your yard writes its own version of Delaware's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
6 of the readings below were taken at Delaware's own scale — the full zone 7a-8a span inside its borders, the 3 soil types that dominate its ground and 6,167 documented sites on its federal record; anything it cannot resolve at this scale is named below.
Measured here
What this page can’t tell you
Explore growing conditions by county — each has its own zone range and land area.
Explore growing conditions by city or town in Delaware.
Delaware shares its dominant growing region with these states — a useful comparison if you're weighing where a crop will behave the same way.
