Suffolk County, in 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.
Reliable performers under these conditions include cabbage, hazelnut, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
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.
Suffolk County holds more than one microclimate.
Soils and elevations shift across Suffolk County, so your frost dates and drainage aren't the county average. 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 Suffolk County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Suffolk County — the short answer
Suffolk County, Massachusetts: USDA zone 7a, about 241 days between hard freezes, across 37K acres.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 28
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 24
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~241
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 37K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 Suffolk County's average, not your lot's — a low corner or a tree line moves it. Against Suffolk County's 241-day season, see what your own ground reads.
Heat in Suffolk County
Across a year, Suffolk County accumulates about 2,709 growing degree days above 50°F, about 183 more than the middle Massachusetts county — ahead of 11 of Massachusetts’s 14 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Suffolk County
Across Suffolk County, the ground is predominantly Inceptisols, where Canton, Merrimac, and Woodbridge are the most extensive named soil series. The soil is generally well drained with a fine sandy loam surface. Topsoil pH runs about 4.6–5.3, very strongly acidic. Rainfall drains through hydrologic group A soils.
Soil order
Inceptisols
Drainage
Well drained
Prime farmland
15%
Hydric soils
20%
Soil still varies lot by lot — soil types explained.
How the ground varies across Suffolk County
The USDA soil survey maps 30% of Suffolk County as well drained — but another 42% drains differently: 11% very poorly drained, 10% somewhat excessively drained.
Canton is the most extensive named soil at 12% of mapped acres, then Merrimac (11%) and Woodbridge (8%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Suffolk County
Each reading below is measured for Suffolk County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Suffolk County are well drained, in hydrologic group A — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Suffolk County runs about pH 4.6–5.3, on the acidic side.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Wet ground
MeasuredAbout 20% of Suffolk County is mapped as hydric — wetland — soil.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Season length
MeasuredSuffolk County runs about 241 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
The kind of country Suffolk County is in
Suffolk County sits in the Northeastern Coastal Zone — EPA Level III, inside the wider Eastern Temperate Forests. One consistent ecological setting across the whole county.
What Grows in Suffolk County
We scored all 1,086 plants against Suffolk County's own USDA zone 7a and its own 241-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Massachusetts profile.
Is it too late to plant in Suffolk County?
For most of the year, no — what changes is which crops still fit the days remaining. 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 24 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
Documented around Suffolk County
Spotted lanternfly documented 10 miles from Suffolk County, first recorded 2020. What to watch for.
- Japanese beetle6 documented records
- monarch butterfly83 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Suffolk County
USGS estimates 21 lb of Imidacloprid on Suffolk County farmland in 2019, its largest by weight, ahead of Halosulfuron (2 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Suffolk County — and how to grow with it.
We checked the federal record across Suffolk County — 2,900 documented sites across 7 of the 9 source types we track.
The most significant on record: 21 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Suffolk County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Suffolk County
Closest first, across Suffolk County. Listing isn't leaking, and distance isn't exposure.
- CASTLE ISLANDBrownfields · 450 ft
- WHITE FUEL DIV OF TEXACO USAUnderground Storage Tanks · 1900 ft
- PAUL W CONLEY TERMINALUnderground Storage Tanks · 1900 ft
- JOHN T CLARK AND SONBrownfields · 1900 ft
- MAGNA ELECTRONICSBrownfields · 2200 ft
- COASTAL OIL OF NEW ENGLANDBrownfields · 2500 ft
- COASTAL OIL OF NEW ENGLANDToxics Release Inventory · 2500 ft
- JOHNS AUTO PLACEBrownfields · 0.5 mi
- MOTIONALBrownfields · 0.6 mi
- JCDECAUX NABrownfields · 0.6 mi
- SOUTH BOSTON NAVAL ANNEXSuperfund · 0.6 mi
- SOUTH BOSTON YACHT CLUBUnderground Storage Tanks · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Suffolk County'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 Suffolk County.
Sources Checked
across Suffolk County
Severity Distribution
across Suffolk County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Suffolk County, Brownfields runs higher than the national average — 2,053 sites across Suffolk County. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around 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 Suffolk County
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 Suffolk County average
Your land is one point inside Suffolk County
Everything above resolves to Suffolk County as a whole — one PHZM band and one county frost record, read across 37K 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 county 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 county average.
Your Lot vs the Suffolk County Average
Suffolk County Average
- ●USDA Zones 7a, averaged across Suffolk County
- ●One soil character for all of Suffolk County
- ●Frost dates read at Suffolk County's scale: Mar 28 to Nov 24
YOUR Parcel
- ✓Your exact zone, not Suffolk County's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Suffolk County
Pull a site-specific report for your exact address in Suffolk County, Massachusetts — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Suffolk County averages can't show:
We read public map data around Suffolk County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Suffolk County average
How we know this about Suffolk County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Suffolk County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Suffolk County
When does frost risk typically end in Suffolk County?
The last hard freeze (28°F) in Suffolk County 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.
How long is the growing season in Suffolk County?
Measured between 28°F hard freezes, Suffolk County sees about 241 frost-free days — roughly Mar 28 through Nov 24, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 18 to Nov 10, about 206 days.
Is the soil safe to grow vegetables in Suffolk County?
The federal record around Suffolk County is a meaningful one — 2,900 documented sites, mostly Brownfields entries (2,053), the nearest Brownfields record under a tenth of a mile 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.
Everything above is measured at Suffolk County's scale — its 7a band and its 241-day season. Your yard writes its own version of Suffolk County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Massachusetts's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Suffolk County’s own scale
9 of the readings below were taken at Suffolk County's own scale — its own ~241-day span between 28°F freezes, the 3 most extensive soil series mapped here and 2,900 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Suffolk County's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Suffolk County's own 28°F hard-freeze dates and its ~241-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Suffolk CountyUSDA NRCS SSURGO
- 2,900 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Brownfields record under a tenth of a mile outFederal environmental registers
- Suffolk County's boundary and the 37,285 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~241-day seasonGrowable Ground crop-matching engine
- Suffolk County sitting wholly inside the Northeastern Coastal ZoneUS EPA Level III Ecoregions
- Open occurrence records documented in Suffolk County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Suffolk County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Massachusetts grower plans around — written at state scale, so they stay on the state guidefrom Massachusetts
What this page can’t tell you
- How the season shifts across Suffolk County — the ~241 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Suffolk County's 37,285 acreswhy one lot differs from the next →
- Which of those 2,900 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Suffolk Countyread your own land →