Onset, Massachusetts, sits in USDA hardiness zone 7a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
On paper, cabbage, hazelnut, california poppy, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
You’re in South Shore
The coastal band south of Boston into old cranberry country — sandy, acidic ground and a maritime season that runs a touch longer than the interior. Bog and shoreline shape what has always grown well down here.
Even in Onset, 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 Onset 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 Onset — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Onset — the short answer
Onset, Massachusetts: USDA zone 7a, about 217 days between hard freezes, across 690 acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 5
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~217
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 690 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 7a is Onset's average, not your lot's — a low corner or a tree line moves it. Against Onset's 217-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Onset
Each reading below is measured for Onset itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredOnset runs about 217 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
MeasuredOnset sits in USDA hardiness zone 7a.
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 Onset is in
Onset sits in the Atlantic Coastal Pine Barrens — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Onset's own centroid, and it is not what its county reads: Plymouth County is mostly Northeastern Coastal Zone. The wider page above you is answering a different question about different ground.
What Grows in Onset
Every plant below cleared Onset's own zone 7a and its 217-day season. Each card opens that plant's Massachusetts profile. How we score.
Is it too late to plant in Onset?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Mar 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 8 — 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 Onset
Spotted lanternfly documented 11 miles from Onset, first recorded 2023. What to watch for.
What's on the federal record near Onset
Closest first, within ~10 miles of Onset. Listing isn't leaking, and distance isn't exposure.
- M & M ENTERPRISESUnderground Storage Tanks · 1900 ft
- ONSET FIRE DISTRICTUnderground Storage Tanks · 2200 ft
- ONSET FIRE DISTRICTBrownfields · 2300 ft
- COUNTRY VETERINARY CLINICBrownfields · 0.7 mi
- MA-WFW 44Nitrate · 0.7 mi
- ATLANTIC BOATS INC D/B/A STONEBRIDGE MARINAUnderground Storage Tanks · 0.7 mi
- DEPOT AUTO SERVICEUnderground Storage Tanks · 0.9 mi
- ONSET FIRE DISTRICTPFAS · 0.9 mi
- CRANBERRY HWY SUNOCOUnderground Storage Tanks · 0.9 mi
- DAINTY MAID PROPERTYUnderground Storage Tanks · 0.9 mi
- LOUS CUSTOM EXHAUSTBrownfields · 1.0 mi
- STOP & SHOP FUEL #474Underground Storage Tanks · 1.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Onset'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 Onset.
Sources Checked
within ~10 miles of Onset
Severity Distribution
within ~10 miles of Onset
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Onset, two things run higher than the national average within ~10 miles of Onset — Nitrate (520 sites) and PFAS (13 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Onset
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 Onset average
Your land is one point inside Onset
Everything above resolves to Onset as a whole — one PHZM band and one 28°F frost record, read across 690 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 Onset Average
Onset Average
- ●USDA Zones 7a, averaged across Onset
- ●One soil character for all of Onset
- ●Frost dates read at Onset's scale: Apr 5 to Nov 8
YOUR Parcel
- ✓Your exact zone, not Onset's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Onset
Pull a site-specific report for your exact address in Onset, Massachusetts — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Onset averages can't show:
We read public map data around Onset — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Onset average
How we know this about Onset
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 Onset’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 Onset
When does frost risk typically end in Onset?
The last hard freeze (28°F) in Onset typically lands around Apr 5, 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 26.
When is the first frost in Onset?
The first hard freeze (28°F) in Onset typically arrives around Nov 8, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 25, so the watching starts about Oct 9 — about 217 days after the spring freeze cleared.
How long is the growing season in Onset?
Measured between 28°F hard freezes, Onset sees about 217 frost-free days — roughly Apr 5 through Nov 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 26 to Oct 25, about 182 days.
Is the soil safe to grow vegetables in Onset?
The federal record around Onset is a meaningful one — 1,100 documented sites, mostly Nitrate entries (520), the nearest Underground Storage Tanks record about 0.4 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 Onset?
From about Oct 9 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 8 (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 8. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Onset's scale — its 7a band and its 217-day season. Your yard writes its own version of Onset'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 Onset’s own scale
7 of the readings below were taken at Onset's own scale — its own ~217-day season between 28°F freezes, the 690 acres it covers and 1,100 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Onset's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Onset's own 28°F hard-freeze dates, about Apr 5 and Nov 8 and the ~217-day span between themNOAA 1991–2020 Climate Normals
- 1,100 documented contamination sites on the federal record near Onset, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- Onset's boundary and the 690 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~217-day seasonGrowable Ground crop-matching engine
- Onset sits in the Atlantic Coastal Pine Barrens — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Onsetlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Onset's 690 acres read through its county's SSURGO summaryfrom Plymouth County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Plymouth 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 Plymouth County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Onset's 690 acreswhy one lot differs from the next →
- Which side of Onset you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 690 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.4 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 Onset-wide figureread your own land →