Dedham, Massachusetts, sits in USDA hardiness zone 6b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
On paper, cabbage, hazelnut, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
You’re in Greater Boston
The state's dense urban core, where growing means raised beds, community plots, and back-lot kitchen gardens more than open field. A long, mild season for the region — but city soil is the thing to know before you dig.
Even in Dedham, 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 Dedham 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 Dedham — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Dedham — the short answer
Dedham, Massachusetts: USDA zone 6b, about 204 days between hard freezes, across 7K acres of town.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~204
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 7K 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 Dedham's average, not your lot's — a low corner or a tree line moves it. Against Dedham's 204-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Dedham
Each reading below is measured for Dedham itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDedham runs about 204 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
MeasuredDedham 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 Dedham is in
Dedham sits in the Northeastern Coastal Zone — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Dedham's own centroid rather than borrowed from Norfolk County.
What Grows in Dedham
Every plant below cleared Dedham's own zone 6b and its 204-day season. Each card opens that plant's Massachusetts profile. How we score.
Is it too late to plant in Dedham?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 11; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 8 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 29 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
Documented around Dedham
Spotted lanternfly documented 0 miles from Dedham, first recorded 2020. What to watch for.
What's on the federal record near Dedham
Closest first, within ~10 miles of Dedham. Listing isn't leaking, and distance isn't exposure.
- NORFOLK COUNTY SUPERIOR COURTHOUSEBrownfields · 1200 ft
- NORFOLK PROBATE AND FAMILY COBrownfields · 1200 ft
- DEDHAM DISTRICT COURTBrownfields · 1300 ft
- DEDHAM EXXONUnderground Storage Tanks · 1400 ft
- DEDHAM FIRE DEPTBrownfields · 1400 ft
- DEDHAM GAS AND SERVICESBrownfields · 1400 ft
- PETRUZZIELLO PROPERTIES LLCBrownfields · 1500 ft
- DEDHAM MAIN POST OFFICEBrownfields · 1500 ft
- VERIZON MASSACHUSETTS #615507Underground Storage Tanks · 1500 ft
- DEDHAM FIRE DEPTUnderground Storage Tanks · 1500 ft
- URSULINE ACADEMYBrownfields · 1500 ft
- VERIZON NEW ENGLAND INCBrownfields · 1600 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Dedham'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 Dedham.
Sources Checked
within ~10 miles of Dedham
Severity Distribution
within ~10 miles of Dedham
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Dedham, Brownfields runs higher than the national average — 4,316 sites within ~10 miles of Dedham. That's not a problem with your land — it's information about it.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Dedham
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 Dedham average
Your land is one point inside Dedham
Everything above resolves to Dedham as a whole — one PHZM band and one 28°F frost record, read across 7K 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 Dedham Average
Dedham Average
- ●USDA Zones 6b, averaged across Dedham
- ●One soil character for all of Dedham
- ●Frost dates read at Dedham's scale: Apr 8 to Oct 29
YOUR Parcel
- ✓Your exact zone, not Dedham's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Dedham
Pull a site-specific report for your exact address in Dedham, Massachusetts — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Dedham averages can't show:
We read public map data around Dedham — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Dedham average
How we know this about Dedham
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 Dedham’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 Dedham
When does frost risk typically end in Dedham?
The last hard freeze (28°F) in Dedham typically lands around Apr 8, 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 29.
When is the first frost in Dedham?
The first hard freeze (28°F) in Dedham typically arrives around Oct 29, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 15, so the watching starts about Sep 29 — about 204 days after the spring freeze cleared.
How long is the growing season in Dedham?
Measured between 28°F hard freezes, Dedham sees about 204 frost-free days — roughly Apr 8 through Oct 29, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 29 to Oct 15, about 169 days.
Is the soil safe to grow vegetables in Dedham?
The federal record around Dedham runs heavier than most — 6,170 documented sites, mostly Brownfields entries (4,316), the nearest Brownfields record about 0.2 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 Dedham?
From about Sep 29 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 29 (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 29. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Dedham's scale — its 6b band and its 204-day season. Your yard writes its own version of Dedham'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 Dedham’s own scale
7 of the readings below were taken at Dedham's own scale — its own ~204-day season between 28°F freezes, the 6,573 acres it covers and 6,170 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Dedham's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Dedham's own 28°F hard-freeze dates, about Apr 8 and Oct 29 and the ~204-day span between themNOAA 1991–2020 Climate Normals
- 6,170 documented contamination sites on the federal record near Dedham, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- Dedham's boundary and the 6,573 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~204-day seasonGrowable Ground crop-matching engine
- The ecoregion at Dedham's own centroid, the Northeastern Coastal ZoneUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Dedhamlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Dedham's 6,573 acres read through its county's SSURGO summaryfrom Norfolk County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Norfolk County
- The growing challenges every Massachusetts grower plans around — written at state scale, so they stay on the state guidefrom Massachusetts
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Norfolk County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Dedham's 6,573 acreswhy one lot differs from the next →
- Which side of Dedham you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 6,573 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.2 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 Dedham-wide figureread your own land →
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