Petersham, Massachusetts, sits in USDA hardiness zone 6a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Growers here do well with cabbage, blackberry, california poppy, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
You’re in Central Massachusetts
The inland heart of the state — rolling upland, cooler nights, and a shorter season than the coast. Stony glacial soils that reward the gardener who feeds and drains them.
Even in Petersham, 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 Petersham 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 Petersham — soil, climate, flood, and parcel records. How we handle your address.
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Petersham — the short answer
Petersham, Massachusetts: USDA zone 6a, about 177 days between hard freezes, across 790 acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~177
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 790 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 6a is Petersham's average, not your lot's — a low corner or a tree line moves it. Against Petersham's 177-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Petersham
Each reading below is measured for Petersham itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredPetersham runs about 177 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
Winter hardiness
MeasuredPetersham sits in USDA hardiness zone 6a.
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 Petersham is in
Petersham sits in the Northeastern Highlands — EPA Level III, inside the wider Northern Forests. That is read at Petersham's own centroid, and it is not what its county reads: Worcester County is mostly Northeastern Coastal Zone. The wider page above you is answering a different question about different ground.
What Grows in Petersham
Every plant below cleared Petersham's own zone 6a and its 177-day season. Each card opens that plant's Massachusetts profile. How we score.
Is it too late to plant in Petersham?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 29; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 26 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 20 — 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 Petersham
Spotted lanternfly documented 15 miles from Petersham, first recorded 2021. What to watch for.
What's on the federal record near Petersham
Closest first, within ~10 miles of Petersham. Listing isn't leaking, and distance isn't exposure.
- SISTERS OF THE ASSUMPTIONUnderground Storage Tanks · 550 ft
- PETERSHAM COUNTRY CLUBUnderground Storage Tanks · 550 ft
- HARVARD FORESTUnderground Storage Tanks · 900 ft
- VERIZON NEW ENGLAND INCBrownfields · 1200 ft
- FREDRIK MARSH ESTATEBrownfields · 1400 ft
- MARIA ASSUMPTA ACADEMYUnderground Storage Tanks · 2000 ft
- CLOUETRE MOTORS INCUnderground Storage Tanks · 0.6 mi
- GARAGE THEBrownfields · 0.6 mi
- MA-KNAULT'S TILL WELLNitrate · 0.8 mi
- PETERSHAM HIGHWAY DEPTUnderground Storage Tanks · 0.9 mi
- MA-PHW 16 PETERSHAM, MANitrate · 1.3 mi
- HARVARD UNIVERSITYBrownfields · 2.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Petersham'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 Petersham.
Total Sites
325
within ~10 miles of Petersham
Risk Level
Elevated
Highest-severity
4 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Petersham
Severity Distribution
within ~10 miles of Petersham
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Petersham, PFAS runs higher than the national average — 4 sites within ~10 miles of Petersham. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Petersham
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 Petersham average
Your land is one point inside Petersham
Everything above resolves to Petersham as a whole — one PHZM band and one 28°F frost record, read across 790 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 Petersham Average
Petersham Average
- ●USDA Zones 6a, averaged across Petersham
- ●One soil character for all of Petersham
- ●Frost dates read at Petersham's scale: Apr 26 to Oct 20
YOUR Parcel
- ✓Your exact zone, not Petersham's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Petersham
Pull a site-specific report for your exact address in Petersham, Massachusetts — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Petersham averages can't show:
We read public map data around Petersham — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Petersham average
How we know this about Petersham
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 Petersham’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 Petersham
When does frost risk typically end in Petersham?
The last hard freeze (28°F) in Petersham typically lands around Apr 26, 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 17.
When is the first frost in Petersham?
The first hard freeze (28°F) in Petersham typically arrives around Oct 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 6, so the watching starts about Sep 20 — about 177 days after the spring freeze cleared.
How long is the growing season in Petersham?
Measured between 28°F hard freezes, Petersham sees about 177 frost-free days — roughly Apr 26 through Oct 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 17 to Oct 6, about 142 days.
Is the soil safe to grow vegetables in Petersham?
The federal record around Petersham is a meaningful one — 325 documented sites, mostly Brownfields entries (142), the nearest Underground Storage Tanks record about 0.1 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 Petersham?
From about Sep 20 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 Oct 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 Oct 20. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Petersham's scale — its 6a band and its 177-day season. Your yard writes its own version of Petersham'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 Petersham’s own scale
7 of the readings below were taken at Petersham's own scale — its own ~177-day season between 28°F freezes, the 790 acres it covers and 325 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Petersham's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Petersham's own 28°F hard-freeze dates, about Apr 26 and Oct 20 and the ~177-day span between themNOAA 1991–2020 Climate Normals
- 325 documented contamination sites on the federal record near Petersham, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Petersham's boundary and the 790 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~177-day seasonGrowable Ground crop-matching engine
- Petersham sits in the Northeastern Highlands — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Petershamlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Petersham's 790 acres read through its county's SSURGO summaryfrom Worcester County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Worcester 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 Worcester County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Petersham's 790 acreswhy one lot differs from the next →
- Which side of Petersham you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 790 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Petersham-wide figureread your own land →
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