Durham, Connecticut, sits in USDA hardiness zone 6b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
These conditions suit cabbage, hazelnut, lavender, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Durham, 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 Durham 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 Durham — soil, climate, flood, and parcel records. How we handle your address.
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Durham — the short answer
Durham, Connecticut: USDA zone 6b, about 207 days between hard freezes, across 5K acres of town.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 6
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~207
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 5K 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 6b is Durham's average, not your lot's — a low corner or a tree line moves it. Against Durham's 207-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Durham
Each reading below is measured for Durham itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDurham runs about 207 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
MeasuredDurham sits in USDA hardiness zone 6b.
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 Durham is in
Durham sits in the Northeastern Coastal Zone — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Durham's own centroid rather than borrowed from Lower Connecticut River Valley Planning Region.
What Grows in Durham
Every plant below cleared Durham's own zone 6b and its 207-day season. Each card opens that plant's Connecticut profile. How we score.
Is it too late to plant in Durham?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 9; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 6 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 30 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
Documented around Durham
Spotted lanternfly documented 4 miles from Durham, first recorded 2022. What to watch for.
What's on the federal record near Durham
Closest first, within ~10 miles of Durham. Listing isn't leaking, and distance isn't exposure.
- FAS MART 313Underground Storage Tanks · 1500 ft
- WALTER HERZIGUnderground Storage Tanks · 1500 ft
- DORAN MANUFACTURING, LLCUnderground Storage Tanks · 1500 ft
- DURHAM MAINTENANCE GARAGEUnderground Storage Tanks · 1500 ft
- RT. 79 MOTORSUnderground Storage Tanks · 1500 ft
- CHARLES W.WIMLERUnderground Storage Tanks · 1500 ft
- DICK'S SUNOCOUnderground Storage Tanks · 1500 ft
- SHELL SERVICE STATIONUnderground Storage Tanks · 1500 ft
- DURHAM SUNOCOUnderground Storage Tanks · 1600 ft
- CT-D 107Nitrate · 2300 ft
- CT-D 50Nitrate · 0.5 mi
- DURHAM MANUFACTURING COMPANYBrownfields · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Durham'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 Durham.
Sources Checked
within ~10 miles of Durham
Severity Distribution
within ~10 miles of Durham
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Durham, Toxics Release Inventory runs higher than the national average — 82 sites within ~10 miles of Durham. That's not a problem with your land — it's information about it.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Durham
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 Durham average
Your land is one point inside Durham
Everything above resolves to Durham as a whole — one PHZM band and one 28°F frost record, read across 5K 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 Durham Average
Durham Average
- ●USDA Zones 6b, averaged across Durham
- ●One soil character for all of Durham
- ●Frost dates read at Durham's scale: Apr 6 to Oct 30
YOUR Parcel
- ✓Your exact zone, not Durham's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Durham
Pull a site-specific report for your exact address in Durham, Connecticut — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Durham averages can't show:
We read public map data around Durham — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Durham average
How we know this about Durham
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 Durham’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 Durham
When does frost risk typically end in Durham?
The last hard freeze (28°F) in Durham typically lands around Apr 6, 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 27.
When is the first frost in Durham?
The first hard freeze (28°F) in Durham typically arrives around Oct 30, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 16, so the watching starts about Sep 30 — about 207 days after the spring freeze cleared.
How long is the growing season in Durham?
Measured between 28°F hard freezes, Durham sees about 207 frost-free days — roughly Apr 6 through Oct 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 27 to Oct 16, about 172 days.
Is the soil safe to grow vegetables in Durham?
The federal record around Durham is a meaningful one — 1,284 documented sites, mostly Underground Storage Tanks entries (593), the nearest Underground Storage Tanks record about 0.3 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 Durham?
From about Sep 30 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 Oct 30 (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 Oct 30. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Durham's scale — its 6b band and its 207-day season. Your yard writes its own version of Durham'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 Durham’s own scale
7 of the readings below were taken at Durham's own scale — its own ~207-day season between 28°F freezes, the 5,279 acres it covers and 1,284 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Durham's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Durham's own 28°F hard-freeze dates, about Apr 6 and Oct 30 and the ~207-day span between themNOAA 1991–2020 Climate Normals
- 1,284 documented contamination sites on the federal record near Durham, the closest Underground Storage Tanks record about 0.3 miles out from the town centreFederal environmental registers
- Durham's boundary and the 5,279 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~207-day seasonGrowable Ground crop-matching engine
- The ecoregion at Durham's own centroid, the Northeastern Coastal ZoneUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Durhamlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Durham's 5,279 acres read through its county's SSURGO summaryfrom Lower Connecticut River Valley County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Lower Connecticut River Valley County
- The growing challenges every Connecticut grower plans around — written at state scale, so they stay on the state guidefrom Connecticut
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Lower Connecticut River Valley County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Durham's 5,279 acreswhy one lot differs from the next →
- Which side of Durham you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 5,279 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.3 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 Durham-wide figureread your own land →