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 honeycrisp apple, wild rice, tomato, and red pine — 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 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Quick Facts
USDA Zones
4a
Last Hard Freeze (28°F)
Apr 19
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Oct 24
County normal — light frosts arrive a few weeks earlier
County Area
1.3M acres
Hardiness Zone Range
Zone maps are averages across Otter Tail County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
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.
What Grows in Otter Tail County
Plants matched to Otter Tail County's USDA zones 4a — each links to its full growing 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 22; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 24 — 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.
Growing Challenges in Minnesota
What an experienced grower plans around here — each one has a move.
Extreme cold (zone 3a: -40F) limits many species
Plant to zone 3 realities and the garden thrives — the hardy-plant palette here is deeper than most catalogs suggest.
Short growing season (100-140 frost-free days)
Start transplants indoors and add a cold frame — the standard Minnesota moves that stretch a short season into a full one.
Heavy clay soils in the Red River Valley
Valley clay grows world-class crops once drainage is handled — raised beds do it instantly, compost does it permanently.
For cultivar selection, pest pressure, and planting-time guidance specific to Minnesota, the University of Minnesota Extension is the authoritative local source.
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.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
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 nearby. 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 1,112 plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Your Specific Parcel Matters
Otter Tail County Average
- ●USDA Zones 4a
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓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 exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Key Growing Facts for Otter Tail County, Minnesota
- USDA Hardiness Zones: 4a (USDA PHZM 2023)
- Last Hard Freeze (28°F): Apr 19 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Oct 24 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~188 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 1.3M acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. County boundaries: US Census TIGER/Line 2025.
Frost dates here are the Otter Tail County average. Low spots and tree cover move them by days on any one yard — see your exact frost windows.
Frequently Asked Questions
What hardiness zone is Otter Tail County, Minnesota?
Otter Tail County sits in USDA hardiness zone 4a, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
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 22; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 24 — 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.
When does frost risk typically end in Otter Tail County?
The last hard freeze (28°F) in Otter Tail County typically lands around Apr 19, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.
How long is the growing season in Otter Tail County?
Measured between 28°F hard freezes, Otter Tail County sees about 188 frost-free days — roughly Apr 19 through Oct 24, per NOAA 1991–2020 climate normals. Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
What vegetables grow in Otter Tail County?
Otter Tail County's zone 4a supports a wide range — strong performers include Honeycrisp Apple, Wild Rice, Tomato, and Red Pine. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Which hardiness zone is Otter Tail County, really?
Officially, Otter Tail County sits in USDA zone 4a (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,112 plants against what's actually there.
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 — 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.
Just moved to Otter Tail County — what should I know before planting?
Start with three facts. Otter Tail County sits in USDA zone 4a, which sets what survives winter; the last 28°F hard freeze typically clears around Apr 19, with about 188 frost-free days to work with (NOAA 1991–2020 climate normals); and 941 documented sites sit on the federal record here, so a soil test before food beds is the smart first step. From there, matching plants to your actual soil and sun is the fun part.
Everything on this page is a Otter Tail County average. Your yard writes its own version — 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.