Dennis, Massachusetts, 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.
On paper, cabbage, prickly pear, california poppy, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
You’re in Cape Cod & the Islands
A sandy, sea-wrapped peninsula and islands with the state's warmest, longest season — and its most maritime one. Acidic soils long worked for cranberries and beach plums; wind and salt are the constant neighbors of every garden.
Even in Dennis, 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 Dennis 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 Dennis — soil, climate, flood, and parcel records. How we handle your address.
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Dennis — the short answer
Dennis, Massachusetts: USDA zone 7b, about 240 days between hard freezes, across 3K acres of town.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 28
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~240
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 3K 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 Dennis's average, not your lot's — a low corner or a tree line moves it. Against Dennis's 240-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Dennis
Each reading below is measured for Dennis itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDennis 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
MeasuredDennis 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 Dennis is in
Dennis sits in the Atlantic Coastal Pine Barrens — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Dennis's own centroid rather than borrowed from Barnstable County.
What Grows in Dennis
Every plant below cleared Dennis's own zone 7b and its 240-day season. Each card opens that plant's Massachusetts profile. How we score.
Is it too late to plant in Dennis?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 28; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 28 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 23 — 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 Dennis
Spotted lanternfly documented 11 miles from Dennis, first recorded 2022. What to watch for.
What's on the federal record near Dennis
Closest first, within ~10 miles of Dennis. Listing isn't leaking, and distance isn't exposure.
- P J NYBERGUnderground Storage Tanks · 1000 ft
- HINCKLEY HOME CENTERUnderground Storage Tanks · 1200 ft
- DENNISPORT AUTOMATIC COIN LAUNDRYBrownfields · 1600 ft
- BASS RIVER MARINABrownfields · 0.6 mi
- CAPE COD FARMS LLCBrownfields · 0.6 mi
- CAPE COD FARMS LLCUnderground Storage Tanks · 0.6 mi
- OLD BASS RIVER ROAD WATER STORAGE TANKBrownfields · 0.7 mi
- FRANK DAHLSTROM DMDBrownfields · 0.7 mi
- DENNIS HIGHLANDS GOLF COURSEBrownfields · 0.8 mi
- DENNIS HIGHLANDS GOLF COURSEUnderground Storage Tanks · 0.8 mi
- DBA RITE AID 10194Brownfields · 1.0 mi
- EXPRESS 936Brownfields · 1.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Dennis'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 Dennis.
Total Sites
804
within ~10 miles of Dennis
Risk Level
Elevated
Highest-severity
4 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Dennis
Severity Distribution
within ~10 miles of Dennis
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Dennis, Brownfields runs higher than the national average — 393 sites within ~10 miles of Dennis. 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 Dennis
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 Dennis average
Your land is one point inside Dennis
Everything above resolves to Dennis as a whole — one PHZM band and one 28°F frost record, read across 3K 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 Dennis Average
Dennis Average
- ●USDA Zones 7b, averaged across Dennis
- ●One soil character for all of Dennis
- ●Frost dates read at Dennis's scale: Mar 28 to Nov 23
YOUR Parcel
- ✓Your exact zone, not Dennis's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Dennis
Pull a site-specific report for your exact address in Dennis, Massachusetts — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Dennis averages can't show:
We read public map data around Dennis — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Dennis average
How we know this about Dennis
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 Dennis’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 Dennis
When does frost risk typically end in Dennis?
The last hard freeze (28°F) in Dennis typically lands around Mar 28, 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 18.
When is the first frost in Dennis?
The first hard freeze (28°F) in Dennis typically arrives around Nov 23, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 9, so the watching starts about Oct 24 — about 240 days after the spring freeze cleared.
How long is the growing season in Dennis?
Measured between 28°F hard freezes, Dennis sees about 240 frost-free days — roughly Mar 28 through Nov 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 18 to Nov 9, about 205 days.
Is the soil safe to grow vegetables in Dennis?
The federal record around Dennis is a meaningful one — 804 documented sites, mostly Brownfields entries (393), the nearest Underground Storage Tanks record about 0.2 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 Dennis?
From about Oct 24 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 23 (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 23. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Dennis's scale — its 7b band and its 240-day season. Your yard writes its own version of Dennis'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 Dennis’s own scale
7 of the readings below were taken at Dennis's own scale — its own ~240-day season between 28°F freezes, the 3,143 acres it covers and 804 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Dennis's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Dennis's own 28°F hard-freeze dates, about Mar 28 and Nov 23 and the ~240-day span between themNOAA 1991–2020 Climate Normals
- 804 documented contamination sites on the federal record near Dennis, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Dennis's boundary and the 3,143 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 Dennis's own centroid, the Atlantic Coastal Pine BarrensUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Dennislydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Dennis's 3,143 acres read through its county's SSURGO summaryfrom Barnstable County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Barnstable 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 Barnstable County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Dennis's 3,143 acreswhy one lot differs from the next →
- Which side of Dennis you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,143 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Dennis-wide figureread your own land →