Mifflin County, in Pennsylvania, sits in USDA hardiness zone 7a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Growers here do well with cabbage, pawpaw, california poppy, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Mifflin County lies within Appalachia — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Mifflin County holds more than one microclimate.
Soils and elevations shift across Mifflin 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 Mifflin County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Mifflin County — the short answer
Mifflin County, Pennsylvania: USDA zone 7a, about 207 days between hard freezes, across 263K acres.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 9
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 2
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~207
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 263K 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 7a is Mifflin County's average, not your lot's — a low corner or a tree line moves it. Against Mifflin County's 207-day season, see what your own ground reads.
Heat in Mifflin County
Across a year, Mifflin County accumulates about 2,702 growing degree days above 50°F, about 155 more than the middle Pennsylvania county — ahead of 42 of Pennsylvania’s 67 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 Mifflin County
Across Mifflin County, the ground is predominantly Inceptisols, where Hazleton, Laidig, and Berks are the most extensive named soil series. The soil is generally well drained with a channery sandy loam surface. Topsoil pH runs about 4.6–5.5, very strongly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Inceptisols
Drainage
Well drained
Prime farmland
12%
Hydric soils
8%
Soil still varies lot by lot — soil types explained.
How the ground varies across Mifflin County
The USDA soil survey maps 80% of Mifflin County as well drained — but another 19% drains differently: 8% moderately well drained, 8% poorly drained.
Hazleton is the most extensive named soil at 21% of mapped acres, then Laidig (14%) and Berks (9%).
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 Mifflin County
Each reading below is measured for Mifflin 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 Mifflin County are well drained, in hydrologic group B — 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 Mifflin County runs about pH 4.6–5.5, 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
Season length
MeasuredMifflin County runs about 207 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
MeasuredMifflin County sits in USDA hardiness zone 7a.
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 Mifflin County is in
Mifflin County sits in the Ridge and Valley — EPA Level III, inside the wider Eastern Temperate Forests. One consistent ecological setting across the whole county.
What Grows in Mifflin County
We scored all 1,086 plants against Mifflin County's own USDA zone 7a and its own 207-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 Pennsylvania profile.
Is it too late to plant in Mifflin County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 2 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
Documented around Mifflin County
Spotted lanternfly documented 2 miles from Mifflin County, first recorded 2020. What to watch for.
- Japanese beetle3 documented records
- monarch butterfly268 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Mifflin County
USGS estimates 35,328 lb of Glyphosate on Mifflin County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (10,690 lb) and Atrazine (9,965 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 Mifflin County — and how to grow with it.
We checked the federal record across Mifflin County — 339 documented sites across 7 of the 9 source types we track.
The most significant on record: 1 Superfund site. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Mifflin County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Mifflin County
Closest first, across Mifflin County. Listing isn't leaking, and distance isn't exposure.
- RYAN SNYDER FARMCAFO · 1.2 mi
- WILLOW BROOK FARMCAFO · 1.6 mi
- DECATUR TWP MIFFLIN CNTYUnderground Storage Tanks · 1.9 mi
- BOWERSOX AUTO BODY INCBrownfields · 2.2 mi
- DAVIS BODY SHOP COLLISION SPECIALIST, INC.Brownfields · 2.3 mi
- MF 273Nitrate · 2.4 mi
- SUNOCO NO 0711-0893Brownfields · 2.4 mi
- WALMART SUPERCENTER NO 1607Brownfields · 2.4 mi
- OPTIMA 0711 0893Underground Storage Tanks · 2.4 mi
- MF 403Nitrate · 2.4 mi
- AGFA NDT INCBrownfields · 2.5 mi
- AGFA NDT INCToxics Release Inventory · 2.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Mifflin 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 Mifflin County.
Sources Checked
across Mifflin County
Severity Distribution
across Mifflin County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mifflin County, two things run higher than the national average across Mifflin County — CAFO (9 sites) and Nitrate (94 sites). That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Mifflin 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 Mifflin County average
Your land is one point inside Mifflin County
Everything above resolves to Mifflin County as a whole — one PHZM band and one county frost record, read across 263K 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 Mifflin County Average
Mifflin County Average
- ●USDA Zones 7a, averaged across Mifflin County
- ●One soil character for all of Mifflin County
- ●Frost dates read at Mifflin County's scale: Apr 9 to Nov 2
YOUR Parcel
- ✓Your exact zone, not Mifflin County's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Mifflin County
Pull a site-specific report for your exact address in Mifflin County, Pennsylvania — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mifflin County averages can't show:
We read public map data around Mifflin County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mifflin County average
How we know this about Mifflin 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 Mifflin County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Mifflin County
When does frost risk typically end in Mifflin County?
The last hard freeze (28°F) in Mifflin County typically lands around Apr 9, 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 30.
How long is the growing season in Mifflin County?
Measured between 28°F hard freezes, Mifflin County sees about 207 frost-free days — roughly Apr 9 through Nov 2, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 30 to Oct 19, about 172 days.
Is the soil safe to grow vegetables in Mifflin County?
The federal record around Mifflin County is a meaningful one — 339 documented sites, mostly Underground Storage Tanks entries (157), the nearest CAFO record about 1.2 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.
Everything above is measured at Mifflin County's scale — its 7a band and its 207-day season. Your yard writes its own version of Mifflin 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 Pennsylvania's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Mifflin County’s own scale
9 of the readings below were taken at Mifflin County's own scale — its own ~207-day span between 28°F freezes, the 3 most extensive soil series mapped here and 339 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Mifflin County's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Mifflin County's own 28°F hard-freeze dates and its ~207-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Mifflin CountyUSDA NRCS SSURGO
- 339 documented contamination sites inside the county boundary, distance-sorted from its center — the closest CAFO record about 1.2 miles outFederal environmental registers
- Mifflin County's boundary and the 263,064 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~207-day seasonGrowable Ground crop-matching engine
- Mifflin County sitting wholly inside the Ridge and ValleyUS EPA Level III Ecoregions
- Open occurrence records documented in Mifflin County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Mifflin County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Pennsylvania grower plans around — written at state scale, so they stay on the state guidefrom Pennsylvania
What this page can’t tell you
- How the season shifts across Mifflin County — the ~207 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 Mifflin County's 263,064 acreswhy one lot differs from the next →
- Which of those 339 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 Mifflin Countyread your own land →