South Ashburnham, Massachusetts, sits in USDA hardiness zone 5b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Well-matched crops include cabbage, cranberry, lavender, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
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 South Ashburnham, 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 South Ashburnham 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 South Ashburnham — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
South Ashburnham — the short answer
South Ashburnham, Massachusetts: USDA zone 5b, about 173 days between hard freezes, across 2K acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 27
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~173
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 2K 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 5b is South Ashburnham's average, not your lot's — a low corner or a tree line moves it. Against South Ashburnham's 173-day season, see what your own ground reads.
Your town runs its own season
South Ashburnham's own 30-year record measures about 173 days between 28°F killing freezes — 32 days shorter than Worcester County's ~205. Both are measured records, not estimates.
That gap is the whole reason a county average can mislead here. Plant against South Ashburnham's ~173-day season rather than the county figure — and the sun, slope and cold-air drainage on your specific lot move it again.
NOAA Regional Climate Centers ACIS (1991–2020), 30-year daily minimum record. Both figures are measured records — this town’s own and its county’s. A town with no record of its own is absent here rather than estimated.
Soil varies lot by lot — soil types explained.
What this means for growing in South Ashburnham
Each reading below is measured for South Ashburnham itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSouth Ashburnham runs about 173 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
MeasuredSouth Ashburnham sits in USDA hardiness zone 5b.
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 South Ashburnham is in
South Ashburnham sits in the Northeastern Highlands — EPA Level III, inside the wider Northern Forests. That is read at South Ashburnham'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 South Ashburnham
Every plant below cleared South Ashburnham's own zone 5b and its 173-day season. Each card opens that plant's Massachusetts profile. How we score.
Is it too late to plant in South Ashburnham?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 30; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 27 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 17 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
Documented around South Ashburnham
Spotted lanternfly documented 9 miles from South Ashburnham, first recorded 2021. What to watch for.
What's on the federal record near South Ashburnham
Closest first, within ~10 miles of South Ashburnham. Listing isn't leaking, and distance isn't exposure.
- JOHN P SPURIA & SONS INCUnderground Storage Tanks · 0.8 mi
- GLOBAL ASHBURNHAMBrownfields · 0.8 mi
- SUPERIOR PLUS ENERGY SERVICES INC ASHBURNHAM OFFICEBrownfields · 0.8 mi
- Global Montello Group #323Underground Storage Tanks · 0.8 mi
- ASHBURNHAM MUNICIPAL LIGHT PLANTBrownfields · 1.0 mi
- ABCROSBY & COMPANY INCBrownfields · 1.4 mi
- OAKMONT REG HIGH SCBrownfields · 1.4 mi
- FE INCBrownfields · 1.6 mi
- CUSHING ACADEMYBrownfields · 1.6 mi
- TERRATHERM INCBrownfields · 1.7 mi
- WOODS EQUIPMENT COToxics Release Inventory · 1.7 mi
- NE PEPTIDE LLC AKA VIVITIDEToxics Release Inventory · 1.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from South Ashburnham'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 South Ashburnham.
Total Sites
699
within ~10 miles of South Ashburnham
Risk Level
Elevated
Highest-severity
12 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of South Ashburnham
Severity Distribution
within ~10 miles of South Ashburnham
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around South Ashburnham, two things run higher than the national average within ~10 miles of South Ashburnham — PFAS (8 sites) and Superfund (12 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in South Ashburnham
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 South Ashburnham average
Your land is one point inside South Ashburnham
Everything above resolves to South Ashburnham as a whole — and this is a town whose own 30-year record already runs a season its county’s does not. Your parcel sits at one point inside even that. 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 South Ashburnham Average
South Ashburnham Average
- ●USDA Zones 5b, averaged across South Ashburnham
- ●One soil character for all of South Ashburnham
- ●Frost dates read at South Ashburnham's scale: Apr 27 to Oct 17
YOUR Parcel
- ✓Your exact zone, not South Ashburnham's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in South Ashburnham
Pull a site-specific report for your exact address in South Ashburnham, Massachusetts — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that South Ashburnham averages can't show:
We read public map data around South Ashburnham — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the South Ashburnham average
How we know this about South Ashburnham
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 South Ashburnham’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 South Ashburnham
When does frost risk typically end in South Ashburnham?
The last hard freeze (28°F) in South Ashburnham typically lands around Apr 27, 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 18.
When is the first frost in South Ashburnham?
The first hard freeze (28°F) in South Ashburnham typically arrives around Oct 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 3, so the watching starts about Sep 17 — about 173 days after the spring freeze cleared.
How long is the growing season in South Ashburnham?
Measured between 28°F hard freezes, South Ashburnham sees about 173 frost-free days — roughly Apr 27 through Oct 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 18 to Oct 3, about 138 days.
Is the soil safe to grow vegetables in South Ashburnham?
The federal record around South Ashburnham is a meaningful one — 699 documented sites, mostly Brownfields entries (397), the nearest Underground Storage Tanks record about 0.8 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 South Ashburnham?
From about Sep 17 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 17 (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 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at South Ashburnham's scale — its 5b band and its 173-day season. Your yard writes its own version of South Ashburnham'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 South Ashburnham’s own scale
7 of the readings below were taken at South Ashburnham's own scale — its own ~173-day season between 28°F freezes, the 1,910 acres it covers and 699 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- South Ashburnham's own USDA hardiness band, zones 5bUSDA PHZM 2023
- South Ashburnham's own 28°F hard-freeze dates, about Apr 27 and Oct 17 and the ~173-day span between themNOAA 1991–2020 Climate Normals
- 699 documented contamination sites on the federal record near South Ashburnham, the closest Underground Storage Tanks record about 0.8 miles out from the town centreFederal environmental registers
- South Ashburnham's boundary and the 1,910 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~173-day seasonGrowable Ground crop-matching engine
- South Ashburnham sits in the Northeastern Highlands — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of South Ashburnhamlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so South Ashburnham's 1,910 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 South Ashburnham's 1,910 acreswhy one lot differs from the next →
- Which side of South Ashburnham you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,910 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.8 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 South Ashburnham-wide figureread your own land →
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