Delaware spans USDA hardiness zones 7a-7b, with a growing season of about 190 frost-free days — enough room for the full run of cool-season vegetables plus warm-season crops that finish before the first hard frost.
Taken together, 42-48 inches of annual rainfall, a median of roughly 3,500 growing-degree days (base 50°F), and about 1,200 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 and Delmarva Peninsula 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 2023•NOAA Climate Normals•USDA NRCS SSURGO•GDD aggregate (Cornell CALS)•Chill-hour aggregate (MSU Extension)•USDA hardiness sub-region map•EPA FRS•USDA PLANTS•Growable Ground suitability scoring
Delaware spans zones 7a-7b, but your yard sits in exactly one — and slope, tree cover, and low spots nudge it further. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — 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.
USDA Zones
7a-7b
USDA PHZM 2023
Last Frost
Apr 1 - Apr 20
NOAA 30-yr Normals
First Frost
Oct 15 - Nov 5
NOAA 30-yr Normals
Annual Rainfall
42-48 inches
NOAA Climate Normals
Zone maps are averages across Delaware. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
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.
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 6, with the middle half of counties between Mar 5 and Mar 7 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Dec 12 and Dec 14 — long-season crops need about 90 days of runway, quick greens only 30. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
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. 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-7b 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 nearby. 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.
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 1,112 plants against the real conditions on your land.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Delaware spans USDA hardiness zones 7a-7b, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
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 6, with the middle half of counties between Mar 5 and Mar 7 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Dec 12 and Dec 14 — long-season crops need about 90 days of runway, quick greens only 30. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
Across Delaware, the middle half of counties see their last hard freeze (28°F) between about Mar 5 and Mar 7, with a county median near Mar 6 (NOAA 1991–2020 climate normals). That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.
Measured between 28°F hard freezes, growing seasons across Delaware's counties mostly run about 280 to 284 days, with a county median near 281 (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-7b 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-7b (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 1,112 plants against what's actually there.
The federal record across Delaware runs heavier than most — 6,167 documented sites — 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-7b, which sets what survives winter; last hard freezes range from about Mar 5 to Mar 7 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 on this page is a Delaware average. Your yard writes its own version — we read soil, sun, drainage, and frost at your exact address. Try it for 14 days — no card required.
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.
