Pennington County, in Minnesota, sits in USDA hardiness zone 3b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Expect cabbage, cranberry, turkish rocket, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Pennington County lies within the Red River Valley — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Pennington County holds more than one microclimate.
Soils and elevations shift across Pennington 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 Pennington County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Pennington County — the short answer
Pennington County, Minnesota: USDA zone 3b, about 161 days between hard freezes, across 395K acres.
- USDA zone
- 3b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 29
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 7
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~161
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 395K 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 3b is Pennington County's average, not your lot's — a low corner or a tree line moves it. Against Pennington County's 161-day season, see what your own ground reads.
Heat in Pennington County
Across a year, Pennington County accumulates about 1,731 growing degree days above 50°F, about 534 fewer than the middle Minnesota county — ahead of 11 of Minnesota’s 87 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 Pennington County
Across Pennington County, the ground is predominantly Mollisols, where Smiley, Kratka, and Reiner are the most extensive named soil series. The soil is generally poorly drained with a fine sandy loam surface. Topsoil pH runs about 7.0–7.5, neutral. Rainfall drains through hydrologic group B/D soils.
Soil order
Mollisols
Drainage
Poorly drained
Prime farmland
19%
Hydric soils
72%
Soil still varies lot by lot — soil types explained.
How the ground varies across Pennington County
The USDA soil survey maps 59% of Pennington County as poorly drained — but another 40% drains differently: 23% moderately well drained, 13% very poorly drained.
Smiley is the most extensive named soil at 19% of mapped acres, then Kratka (13%) and Reiner (12%).
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 Pennington County
Each reading below is measured for Pennington 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 Pennington County are poorly drained, in hydrologic group B/D — ground that sheds water slowly.
Beds can stay saturated for days after heavy rain, and the roots of most vegetables, berries, and fruit trees suffocate or rot in soil that never drains.
Raised beds or mounded rows lift roots above the wet zone; choose water-tolerant crops for the lowest spots.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Pennington County runs about pH 7.0–7.5, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredPennington County runs about 161 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
MeasuredPennington County sits in USDA hardiness zone 3b.
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 Pennington County is in
Pennington County sits in the Lake Agassiz Plain — EPA Level III, inside the wider Great Plains. One consistent ecological setting across the whole county.
What Grows in Pennington County
We scored all 1,086 plants against Pennington County's own USDA zone 3b and its own 161-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 Minnesota profile.
Is it too late to plant in Pennington County?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 29 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 7 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What gets applied to farmland in Pennington County
USGS estimates 125,297 lb of Glyphosate on Pennington County farmland in 2019, its largest by weight, ahead of Bromoxynil (16,531 lb) and Metolachlor & Metolachlor-s (14,506 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 Pennington County — and how to grow with it.
We checked the federal record across Pennington County — 164 documented sites across 5 of the 9 source types we track.
The most significant on record: 6 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
The federal record across Pennington County is a modest one — a typical footprint for a growing area. Nothing here calls for alarm; it's worth knowing which recorded sites sit closest to where you grow, and each one on the map carries its type and location. If one turns out to be a near neighbor, a one-time soil test settles the question.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Pennington County
Closest first, across Pennington County. Listing isn't leaking, and distance isn't exposure.
- 513239Nitrate · 4.3 mi
- GALAXIE AUTO SALESBrownfields · 4.6 mi
- 455391Nitrate · 4.7 mi
- NORTHWEST MEDICAL CENTERBrownfields · 4.9 mi
- THIEF RIVER CARE CENTERBrownfields · 5.6 mi
- New C-StoreUnderground Storage Tanks · 5.7 mi
- VALLEY ANIMAL HOSPITALBrownfields · 5.8 mi
- DALE'S AUTO REPAIRBrownfields · 5.8 mi
- ALTRU CLINIC - THIEF RIVER FABrownfields · 5.9 mi
- WAL-MART SUPERCENTER 3761Brownfields · 6.0 mi
- O'REILLY AUTO PARTS - 1519Brownfields · 6.0 mi
- Murphy Oil Co #7308Underground Storage Tanks · 6.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Pennington 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 Pennington County.
Total Sites
164
across Pennington County
Risk Level
Moderate
Highest-severity
6 Toxics Release Inventory facilities
Sources Checked
across Pennington County
Severity Distribution
across Pennington County
Highest-Severity Sites
Know Before You Grow
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Pennington 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 Pennington County average
Your land is one point inside Pennington County
Everything above resolves to Pennington County as a whole — one PHZM band and one county frost record, read across 395K 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 Pennington County Average
Pennington County Average
- ●USDA Zones 3b, averaged across Pennington County
- ●One soil character for all of Pennington County
- ●Frost dates read at Pennington County's scale: Apr 29 to Oct 7
YOUR Parcel
- ✓Your exact zone, not Pennington County's 3b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Pennington County
Pull a site-specific report for your exact address in Pennington County, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Pennington County averages can't show:
We read public map data around Pennington County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Pennington County average
How we know this about Pennington 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 Pennington County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Pennington County
When does frost risk typically end in Pennington County?
The last hard freeze (28°F) in Pennington County typically lands around Apr 29, 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 20.
How long is the growing season in Pennington County?
Measured between 28°F hard freezes, Pennington County sees about 161 frost-free days — roughly Apr 29 through Oct 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 20 to Sep 23, about 126 days.
Is the soil safe to grow vegetables in Pennington County?
The federal record around Pennington County shows 164 documented sites, mostly Brownfields entries (73), the nearest Nitrate record about 4.3 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
Everything above is measured at Pennington County's scale — its 3b band and its 161-day season. Your yard writes its own version of Pennington 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 Minnesota's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Pennington County’s own scale
8 of the readings below were taken at Pennington County's own scale — its own ~161-day span between 28°F freezes, the 3 most extensive soil series mapped here and 164 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Pennington County's own USDA hardiness band, zones 3bUSDA PHZM 2023
- Pennington County's own 28°F hard-freeze dates and its ~161-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Pennington CountyUSDA NRCS SSURGO
- 164 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 4.3 miles outFederal environmental registers
- Pennington County's boundary and the 394,572 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 3b and a ~161-day seasonGrowable Ground crop-matching engine
- Pennington County sitting wholly inside the Lake Agassiz PlainUS EPA Level III Ecoregions
- Which agricultural compounds go onto Pennington County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Minnesota grower plans around — written at state scale, so they stay on the state guidefrom Minnesota
What this page can’t tell you
- How the season shifts across Pennington County — the ~161 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 Pennington County's 394,572 acreswhy one lot differs from the next →
- Which of those 164 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 Pennington Countyread your own land →