Mammoth, Pennsylvania, sits in USDA hardiness zone 6b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
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.
Even in Mammoth, 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 Mammoth 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 Mammoth — soil, climate, flood, and parcel records. How we handle your address.
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Mammoth — the short answer
Mammoth, Pennsylvania: USDA zone 6b, about 184 days between hard freezes, across 1K acres of town.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 22
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~184
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 6b is Mammoth's average, not your lot's — a low corner or a tree line moves it. Against Mammoth's 184-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Mammoth
Each reading below is measured for Mammoth itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMammoth runs about 184 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
MeasuredMammoth sits in USDA hardiness zone 6b.
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 Mammoth is in
Mammoth sits in the Western Allegheny Plateau — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Mammoth's own centroid rather than borrowed from Westmoreland County.
What Grows in Mammoth
Every plant below cleared Mammoth's own zone 6b and its 184-day season. Each card opens that plant's Pennsylvania profile. How we score.
Is it too late to plant in Mammoth?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 25; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 22 (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. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
Documented around Mammoth
Spotted lanternfly documented 3 miles from Mammoth, first recorded 2023. What to watch for.
What's on the federal record near Mammoth
Closest first, within ~10 miles of Mammoth. Listing isn't leaking, and distance isn't exposure.
- MT PLEASANT TWP WESTMORELAND CNTYUnderground Storage Tanks · 600 ft
- CITIZENS TELE CO OF KECKSBURGUnderground Storage Tanks · 1000 ft
- ELECTRO GLASSBrownfields · 1100 ft
- WE 150Nitrate · 0.8 mi
- WE 135Nitrate · 1.0 mi
- WE 310Nitrate · 1.0 mi
- NORVELT GULFUnderground Storage Tanks · 1.1 mi
- JOSEPH J SOSKOUnderground Storage Tanks · 1.5 mi
- SMOUSE TRUCKS VANS INCBrownfields · 1.7 mi
- COUNTRY AUTO BODYBrownfields · 1.8 mi
- NORVELT BP 891Underground Storage Tanks · 1.9 mi
- OPEN PANTRY FOOD MARTSUnderground Storage Tanks · 1.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Mammoth'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 Mammoth.
Total Sites
751
within ~10 miles of Mammoth
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Mammoth
Severity Distribution
within ~10 miles of Mammoth
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •TRI facilities report what they release. Check the wind — downwind beds catch more of it.
Check your specific parcel in Mammoth
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 Mammoth average
Your land is one point inside Mammoth
Everything above resolves to Mammoth as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Mammoth Average
Mammoth Average
- ●USDA Zones 6b, averaged across Mammoth
- ●One soil character for all of Mammoth
- ●Frost dates read at Mammoth's scale: Apr 22 to Oct 23
YOUR Parcel
- ✓Your exact zone, not Mammoth's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Mammoth
Pull a site-specific report for your exact address in Mammoth, Pennsylvania — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mammoth averages can't show:
We read public map data around Mammoth — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mammoth average
How we know this about Mammoth
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 Mammoth’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 Mammoth
When does frost risk typically end in Mammoth?
The last hard freeze (28°F) in Mammoth typically lands around Apr 22, 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 13.
When is the first frost in Mammoth?
The first hard freeze (28°F) in Mammoth typically arrives around Oct 23, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 9, so the watching starts about Sep 23 — about 184 days after the spring freeze cleared.
How long is the growing season in Mammoth?
Measured between 28°F hard freezes, Mammoth sees about 184 frost-free days — roughly Apr 22 through Oct 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 13 to Oct 9, about 149 days.
Is the soil safe to grow vegetables in Mammoth?
The federal record around Mammoth is a meaningful one — 751 documented sites, mostly Underground Storage Tanks entries (367), 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 Mammoth?
From about Sep 23 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 23 (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 23. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Mammoth's scale — its 6b band and its 184-day season. Your yard writes its own version of Mammoth'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 Mammoth’s own scale
7 of the readings below were taken at Mammoth's own scale — its own ~184-day season between 28°F freezes, the 1,294 acres it covers and 751 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Mammoth's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Mammoth's own 28°F hard-freeze dates, about Apr 22 and Oct 23 and the ~184-day span between themNOAA 1991–2020 Climate Normals
- 751 documented contamination sites on the federal record near Mammoth, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Mammoth's boundary and the 1,294 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~184-day seasonGrowable Ground crop-matching engine
- The ecoregion at Mammoth's own centroid, the Western Allegheny PlateauUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Mammothlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Mammoth's 1,294 acres read through its county's SSURGO summaryfrom Westmoreland County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Westmoreland County
- The growing challenges every Pennsylvania grower plans around — written at state scale, so they stay on the state guidefrom Pennsylvania
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Westmoreland County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Mammoth's 1,294 acreswhy one lot differs from the next →
- Which side of Mammoth you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,294 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 Mammoth-wide figureread your own land →
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