Northwest Harwich, 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.
Expect cabbage, prickly pear, california poppy, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
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 Northwest Harwich, 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 Northwest Harwich 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 Northwest Harwich — soil, climate, flood, and parcel records. How we handle your address.
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Northwest Harwich — the short answer
Northwest Harwich, Massachusetts: USDA zone 7b, about 234 days between hard freezes, across 5K acres of town.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 31
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~234
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 5K 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 Northwest Harwich's average, not your lot's — a low corner or a tree line moves it. Against Northwest Harwich's 234-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Northwest Harwich
Each reading below is measured for Northwest Harwich itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredNorthwest Harwich runs about 234 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
MeasuredNorthwest Harwich 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 Northwest Harwich is in
Northwest Harwich sits in the Atlantic Coastal Pine Barrens — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Northwest Harwich's own centroid rather than borrowed from Barnstable County.
What Grows in Northwest Harwich
Every plant below cleared Northwest Harwich's own zone 7b and its 234-day season. Each card opens that plant's Massachusetts profile. How we score.
Is it too late to plant in Northwest Harwich?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 3; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 31 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 20 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
Documented around Northwest Harwich
Spotted lanternfly documented 14 miles from Northwest Harwich, first recorded 2022. What to watch for.
What's on the federal record near Northwest Harwich
Closest first, within ~10 miles of Northwest Harwich. Listing isn't leaking, and distance isn't exposure.
- RONALD J KENDALLUnderground Storage Tanks · 1100 ft
- CAPE DISCOUNT FUELUnderground Storage Tanks · 1300 ft
- CRANBERRY COLLISIONBrownfields · 2300 ft
- HANDLERS AUTO PARTSBrownfields · 2300 ft
- T&T AUTO CAREBrownfields · 2300 ft
- OBRIEN & STALKER INCBrownfields · 2500 ft
- O'BRIEN & STALKER INCUnderground Storage Tanks · 2500 ft
- OUR ROBERT B CO INCBrownfields · 0.5 mi
- HARWICH SANITARY LANDFILLSuperfund · 0.6 mi
- HARWICH SOLAR AQUATICS FACILITBrownfields · 0.6 mi
- HARWICH SANITARY LANDFILLBrownfields · 0.6 mi
- HARWICH DEPT OF PUBLIC WORKSBrownfields · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Northwest Harwich'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 Northwest Harwich.
Total Sites
955
within ~10 miles of Northwest Harwich
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Northwest Harwich
Severity Distribution
within ~10 miles of Northwest Harwich
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Northwest Harwich, Nitrate runs higher than the national average — 366 sites within ~10 miles of Northwest Harwich. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Northwest Harwich
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 Northwest Harwich average
Your land is one point inside Northwest Harwich
Everything above resolves to Northwest Harwich as a whole — one PHZM band and one 28°F frost record, read across 5K 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 Northwest Harwich Average
Northwest Harwich Average
- ●USDA Zones 7b, averaged across Northwest Harwich
- ●One soil character for all of Northwest Harwich
- ●Frost dates read at Northwest Harwich's scale: Mar 31 to Nov 20
YOUR Parcel
- ✓Your exact zone, not Northwest Harwich's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Northwest Harwich
Pull a site-specific report for your exact address in Northwest Harwich, Massachusetts — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Northwest Harwich averages can't show:
We read public map data around Northwest Harwich — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Northwest Harwich average
How we know this about Northwest Harwich
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 Northwest Harwich’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 Northwest Harwich
When does frost risk typically end in Northwest Harwich?
The last hard freeze (28°F) in Northwest Harwich typically lands around Mar 31, 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 21.
When is the first frost in Northwest Harwich?
The first hard freeze (28°F) in Northwest Harwich typically arrives around Nov 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 6, so the watching starts about Oct 21 — about 234 days after the spring freeze cleared.
How long is the growing season in Northwest Harwich?
Measured between 28°F hard freezes, Northwest Harwich sees about 234 frost-free days — roughly Mar 31 through Nov 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 21 to Nov 6, about 199 days.
Is the soil safe to grow vegetables in Northwest Harwich?
The federal record around Northwest Harwich is a meaningful one — 955 documented sites, mostly Nitrate entries (366), 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 Northwest Harwich?
From about Oct 21 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 20 (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 20. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Northwest Harwich's scale — its 7b band and its 234-day season. Your yard writes its own version of Northwest Harwich'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 Northwest Harwich’s own scale
7 of the readings below were taken at Northwest Harwich's own scale — its own ~234-day season between 28°F freezes, the 5,109 acres it covers and 955 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Northwest Harwich's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Northwest Harwich's own 28°F hard-freeze dates, about Mar 31 and Nov 20 and the ~234-day span between themNOAA 1991–2020 Climate Normals
- 955 documented contamination sites on the federal record near Northwest Harwich, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Northwest Harwich's boundary and the 5,109 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~234-day seasonGrowable Ground crop-matching engine
- The ecoregion at Northwest Harwich's own centroid, the Atlantic Coastal Pine BarrensUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Northwest Harwichlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Northwest Harwich's 5,109 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 Northwest Harwich's 5,109 acreswhy one lot differs from the next →
- Which side of Northwest Harwich you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 5,109 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 Northwest Harwich-wide figureread your own land →