Middlesex County, in Massachusetts, 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.
The conditions favor cabbage, blackberry, california poppy, and collard greens, among others — though every individual site edits that list with its own 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.
Middlesex County holds more than one microclimate.
Soils and elevations shift across Middlesex 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 Middlesex County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Middlesex County — the short answer
Middlesex County, Massachusetts: USDA zone 6b, about 193 days between hard freezes, across 523K acres.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 13
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 23
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~193
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 523K 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 6b is Middlesex County's average, not your lot's — a low corner or a tree line moves it. Against Middlesex County's 193-day season, see what your own ground reads.
Heat in Middlesex County
Across a year, Middlesex County accumulates about 2,544 growing degree days above 50°F, about 18 more than the middle Massachusetts county — ahead of 7 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 Middlesex County
Across Middlesex County, the ground is predominantly Inceptisols, where Charlton, Freetown, and Hinckley are the most extensive named soil series. The soil is generally well drained with a fine sandy loam surface. Topsoil pH runs about 5.0–5.3, strongly acidic. Rainfall drains through hydrologic group A soils.
Soil order
Inceptisols
Drainage
Well drained
Prime farmland
11%
Hydric soils
21%
Soil still varies lot by lot — soil types explained.
How the ground varies across Middlesex County
The USDA soil survey maps 34% of Middlesex County as well drained — but another 50% drains differently: 14% very poorly drained, 14% excessively drained.
Charlton is the most extensive named soil at 8% of mapped acres, then Freetown (8%) and Hinckley (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 Middlesex County
Each reading below is measured for Middlesex 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 Middlesex 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 Middlesex County runs about pH 5.0–5.3, 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 21% of Middlesex 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
MeasuredMiddlesex County runs about 193 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
The kind of country Middlesex County is in
Middlesex 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 Middlesex County
We scored all 1,086 plants against Middlesex County's own USDA zone 6b and its own 193-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 Middlesex County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 16; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 23 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
Documented around Middlesex County
Spotted lanternfly documented 3 miles from Middlesex County, first recorded 2020. What to watch for.
- Japanese beetle71 documented records
- monarch butterfly481 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Middlesex County
USGS estimates 538 lb of Glyphosate on Middlesex County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (459 lb) and Metolachlor-s (304 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 Middlesex County — and how to grow with it.
We checked the federal record across Middlesex County — 8,635 documented sites across 7 of the 9 source types we track.
The most significant on record: 105 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Middlesex County carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Middlesex County
Closest first, across Middlesex County. Listing isn't leaking, and distance isn't exposure.
- SIMS ENGINEERINGBrownfields · 0.8 mi
- MOBIL 2476Brownfields · 0.8 mi
- PETES AUTOMOTIVE REPAIRBrownfields · 0.8 mi
- GLOBAL MONTELLO GROUP #1476Underground Storage Tanks · 0.8 mi
- INTERNATIONAL COLLISION CENTERBrownfields · 0.9 mi
- BURSAW GAS & OIL INC.Brownfields · 0.9 mi
- BURSAW GAS & OIL INCUnderground Storage Tanks · 1.0 mi
- NORTHEASTERN CORRECTIONAL CENTERUnderground Storage Tanks · 1.0 mi
- NORTHEAST CORRECTIONAL CENTERBrownfields · 1.0 mi
- MASSDOT FACILITY 63Underground Storage Tanks · 1.0 mi
- PMG #8634/8708Underground Storage Tanks · 1.0 mi
- MASS STATE POLICEUnderground Storage Tanks · 1.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Middlesex 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 Middlesex County.
Sources Checked
across Middlesex County
Severity Distribution
across Middlesex County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Middlesex County, Brownfields runs higher than the national average — 5,878 sites across Middlesex County. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Middlesex 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 Middlesex County average
Your land is one point inside Middlesex County
Everything above resolves to Middlesex County as a whole — one PHZM band and one county frost record, read across 523K 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 Middlesex County Average
Middlesex County Average
- ●USDA Zones 6b, averaged across Middlesex County
- ●One soil character for all of Middlesex County
- ●Frost dates read at Middlesex County's scale: Apr 13 to Oct 23
YOUR Parcel
- ✓Your exact zone, not Middlesex County's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Middlesex County
Pull a site-specific report for your exact address in Middlesex County, Massachusetts — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Middlesex County averages can't show:
We read public map data around Middlesex County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Middlesex County average
How we know this about Middlesex 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 Middlesex County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Middlesex County
When does frost risk typically end in Middlesex County?
The last hard freeze (28°F) in Middlesex County typically lands around Apr 13, 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 May 4.
How long is the growing season in Middlesex County?
Measured between 28°F hard freezes, Middlesex County sees about 193 frost-free days — roughly Apr 13 through Oct 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 4 to Oct 9, about 158 days.
Is the soil safe to grow vegetables in Middlesex County?
The federal record around Middlesex County runs heavier than most — 8,635 documented sites, mostly Brownfields entries (5,878), the nearest Brownfields record about 0.8 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.
Everything above is measured at Middlesex County's scale — its 6b band and its 193-day season. Your yard writes its own version of Middlesex 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 Middlesex County’s own scale
9 of the readings below were taken at Middlesex County's own scale — its own ~193-day span between 28°F freezes, the 3 most extensive soil series mapped here and 8,635 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Middlesex County's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Middlesex County's own 28°F hard-freeze dates and its ~193-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Middlesex CountyUSDA NRCS SSURGO
- 8,635 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Brownfields record about 0.8 miles outFederal environmental registers
- Middlesex County's boundary and the 523,458 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~193-day seasonGrowable Ground crop-matching engine
- Middlesex County sitting wholly inside the Northeastern Coastal ZoneUS EPA Level III Ecoregions
- Open occurrence records documented in Middlesex County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Middlesex 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 Middlesex County — the ~193 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 Middlesex County's 523,458 acreswhy one lot differs from the next →
- Which of those 8,635 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 Middlesex Countyread your own land →