Otter Tail County, in Minnesota, sits in USDA hardiness zone 4a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Crops well matched to these conditions include cabbage, cranberry, turkish rocket, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Otter Tail County holds more than one microclimate.
Soils and elevations shift across Otter Tail 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 Otter Tail County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Otter Tail County — the short answer
Otter Tail County, Minnesota: USDA zone 4a, about 172 days between hard freezes, across 1.3M acres.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 25
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 14
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~172
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.3M 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 4a is Otter Tail County's average, not your lot's — a low corner or a tree line moves it. Against Otter Tail County's 172-day season, see what your own ground reads.
Heat in Otter Tail County
Across a year, Otter Tail County accumulates about 2,046 growing degree days above 50°F, about 219 fewer than the middle Minnesota county — ahead of 26 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 Otter Tail County
Across Otter Tail County, the ground is predominantly Mollisols, where Dorset, Kandota, and Seelyeville are the most extensive named soil series. The soil is generally well drained with a sandy loam surface. Topsoil pH runs about 6.5–7.0, neutral. Rainfall drains through hydrologic group B soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
20%
Hydric soils
25%
Soil still varies lot by lot — soil types explained.
How the ground varies across Otter Tail County
The USDA soil survey maps 38% of Otter Tail County as well drained — but another 51% drains differently: 15% very poorly drained, 13% moderately well drained.
Dorset is the most extensive named soil at 6% of mapped acres, then Kandota (5%) and Seelyeville (5%).
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 Otter Tail County
Each reading below is measured for Otter Tail 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 Otter Tail 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 Otter Tail County runs about pH 6.5–7.0, 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
Wet ground
MeasuredAbout 25% of Otter Tail County is mapped as hydric — wetland — soil.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Season length
MeasuredOtter Tail County runs about 172 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
The kind of country Otter Tail County is in
Otter Tail County spans 2 EPA Level III ecoregions — North Central Hardwood Forests (93%) and Lake Agassiz Plain (7%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Otter Tail County
We scored all 1,086 plants against Otter Tail County's own USDA zone 4a and its own 172-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 Otter Tail 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 Mar 28; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 25 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 14 — 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 Otter Tail County
- monarch butterfly1,549 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Otter Tail County
USGS estimates 347,170 lb of Glyphosate on Otter Tail County farmland in 2019, its largest by weight, ahead of Acetochlor (129,307 lb) and Metolachlor & Metolachlor-s (98,146 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 Otter Tail County — and how to grow with it.
We checked the federal record across Otter Tail County — 941 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 Otter Tail 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 Otter Tail County
Closest first, across Otter Tail County. Listing isn't leaking, and distance isn't exposure.
- West Central Airways IncUnderground Storage Tanks · 2200 ft
- Hegstad Oil CoUnderground Storage Tanks · 2200 ft
- 134N40W15AADB 01Nitrate · 1.5 mi
- 134N40W32AAA 01 0000488040Nitrate · 2.1 mi
- Barkys ResortUnderground Storage Tanks · 2.5 mi
- The Corner Store on Otter Tail LakeUnderground Storage Tanks · 2.8 mi
- 516466Nitrate · 2.9 mi
- 134N40W30CAB01Nitrate · 3.1 mi
- 525038Nitrate · 3.7 mi
- 133N40W11ADCA 01Nitrate · 4.2 mi
- MM17 134N41W23ACCDAC01 0000244264Nitrate · 4.5 mi
- 134N41W14DABB 01Nitrate · 4.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Otter Tail 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 Otter Tail County.
Sources Checked
across Otter Tail County
Severity Distribution
across Otter Tail County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Otter Tail County, Nitrate runs higher than the national average — 464 sites across Otter Tail County. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Otter Tail 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 Otter Tail County average
Your land is one point inside Otter Tail County
Everything above resolves to Otter Tail County as a whole — one PHZM band and one county frost record, read across 1.3M 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 Otter Tail County Average
Otter Tail County Average
- ●USDA Zones 4a, averaged across Otter Tail County
- ●One soil character for all of Otter Tail County
- ●Frost dates read at Otter Tail County's scale: Apr 25 to Oct 14
YOUR Parcel
- ✓Your exact zone, not Otter Tail County's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Otter Tail County
Pull a site-specific report for your exact address in Otter Tail County, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Otter Tail County averages can't show:
We read public map data around Otter Tail County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Otter Tail County average
How we know this about Otter Tail 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 Otter Tail County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Otter Tail County
When does frost risk typically end in Otter Tail County?
The last hard freeze (28°F) in Otter Tail County typically lands around Apr 25, 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 16.
How long is the growing season in Otter Tail County?
Measured between 28°F hard freezes, Otter Tail County sees about 172 frost-free days — roughly Apr 25 through Oct 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 16 to Sep 30, about 137 days.
Is the soil safe to grow vegetables in Otter Tail County?
The federal record around Otter Tail County is a meaningful one — 941 documented sites, mostly Nitrate entries (464), the nearest Underground Storage Tanks record about 0.4 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 Otter Tail County's scale — its 4a band and its 172-day season. Your yard writes its own version of Otter Tail 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 Otter Tail County’s own scale
9 of the readings below were taken at Otter Tail County's own scale — its own ~172-day span between 28°F freezes, the 3 most extensive soil series mapped here and 941 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Otter Tail County's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Otter Tail County's own 28°F hard-freeze dates and its ~172-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Otter Tail CountyUSDA NRCS SSURGO
- 941 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 0.4 miles outFederal environmental registers
- Otter Tail County's boundary and the 1,261,846 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~172-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Otter Tail County spans, North Central Hardwood Forests the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Otter Tail County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Otter Tail 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 Otter Tail County — the ~172 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 Otter Tail County's 1,261,846 acreswhy one lot differs from the next →
- Which of those 941 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 Otter Tail Countyread your own land →