Olmsted County, in Minnesota, sits in USDA hardiness zone 4b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Expect honeycrisp apple, wild rice, tomato, and red pine to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Olmsted County lies within the Driftless Area — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Olmsted County holds more than one microclimate.
Soils and elevations shift across Olmsted 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.
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Quick Facts
USDA Zones
4b
Last Hard Freeze (28°F)
Apr 11
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Oct 30
County normal — light frosts arrive a few weeks earlier
County Area
418K acres
Hardiness Zone Range
Zone maps are averages across Olmsted County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in Olmsted County
Across Olmsted County, the ground is predominantly Mollisols, where Downs, Tama, and Rockton are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 6.2–6.7, slightly acidic. Rainfall drains through hydrologic group C soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
53%
Hydric soils
12%
Soil still varies lot by lot — soil types explained.
What Grows in Olmsted County
Plants matched to Olmsted County's USDA zones 4b — each links to its full growing profile.
Is it too late to plant in Olmsted County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 11 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 30 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the 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 Olmsted County — and how to grow with it.
We checked the federal record across Olmsted County — 1,085 documented sites across 7 of the 9 source types we track.
The most significant on record: 3 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Olmsted County carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
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 Olmsted County
Severity Distribution
across Olmsted County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Olmsted County, two things run higher than the national average — Brownfields (592 sites) and CAFO (10 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check your specific parcel in Olmsted 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
Olmsted County Average
- ●USDA Zones 4b
- ●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 Olmsted County
Pull a site-specific report for your exact address in Olmsted 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 Olmsted County, Minnesota
- USDA Hardiness Zones: 4b (USDA PHZM 2023)
- Last Hard Freeze (28°F): Apr 11 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Oct 30 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~202 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 418K 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 Olmsted 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 Olmsted County, Minnesota?
Olmsted County sits in USDA hardiness zone 4b, 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 Olmsted County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 11 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 30 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
When does frost risk typically end in Olmsted County?
The last hard freeze (28°F) in Olmsted County typically lands around Apr 11, 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 Olmsted County?
Measured between 28°F hard freezes, Olmsted County sees about 202 frost-free days — roughly Apr 11 through Oct 30, 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 Olmsted County?
Olmsted County's zone 4b 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 Olmsted County, really?
Officially, Olmsted County sits in USDA zone 4b (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 Olmsted County?
The federal record around Olmsted County runs heavier than most — 1,085 documented sites — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Just moved to Olmsted County — what should I know before planting?
Start with three facts. Olmsted County sits in USDA zone 4b, which sets what survives winter; the last 28°F hard freeze typically clears around Apr 11, with about 202 frost-free days to work with (NOAA 1991–2020 climate normals); and 1,085 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 Olmsted 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.