Underwood, Minnesota, sits in USDA hardiness zone 4a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
These conditions suit cabbage, cranberry, turkish rocket, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Underwood, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Underwood lot. 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 Underwood — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Underwood — the short answer
Underwood, Minnesota: USDA zone 4a, about 172 days between hard freezes, across 376 acres of city.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 24
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 13
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~172
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 376 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 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 Underwood's average, not your lot's — a low corner or a tree line moves it. Against Underwood's 172-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Underwood
Each reading below is measured for Underwood itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredUnderwood 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
Winter hardiness
MeasuredUnderwood sits in USDA hardiness zone 4a.
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 Underwood is in
Underwood sits in the North Central Hardwood Forests — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Underwood's own centroid rather than borrowed from Otter Tail County.
What Grows in Underwood
Every plant below cleared Underwood's own zone 4a and its 172-day season. Each card opens that plant's Minnesota profile. How we score.
Is it too late to plant in Underwood?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 27; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 24 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 13 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
What's on the federal record near Underwood
Closest first, within ~10 miles of Underwood. Listing isn't leaking, and distance isn't exposure.
- Jims Service Oil Farm CenterUnderground Storage Tanks · 2100 ft
- Underwood Oil CoUnderground Storage Tanks · 2100 ft
- Under MartUnderground Storage Tanks · 0.6 mi
- 519537Nitrate · 2.7 mi
- Shady Nook ResortUnderground Storage Tanks · 3.0 mi
- Alpha Country RepairUnderground Storage Tanks · 3.0 mi
- Peterson Leroy IUnderground Storage Tanks · 3.0 mi
- Conoco - Quick StopUnderground Storage Tanks · 3.0 mi
- Formerly Maine Grocery StoreUnderground Storage Tanks · 3.0 mi
- 516449Nitrate · 3.7 mi
- 513978Nitrate · 3.9 mi
- FERGUS POWER PUMP INCBrownfields · 4.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Underwood'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 Underwood.
Total Sites
182
within ~10 miles of Underwood
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Underwood
Severity Distribution
within ~10 miles of Underwood
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Underwood, Nitrate runs higher than the national average — 56 sites within ~10 miles of Underwood. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Underwood
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 Underwood average
Your land is one point inside Underwood
Everything above resolves to Underwood as a whole — one PHZM band and one 28°F frost record, read across 376 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 city 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 local average.
Your Lot vs the Underwood Average
Underwood Average
- ●USDA Zones 4a, averaged across Underwood
- ●One soil character for all of Underwood
- ●Frost dates read at Underwood's scale: Apr 24 to Oct 13
YOUR Parcel
- ✓Your exact zone, not Underwood's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Underwood
Pull a site-specific report for your exact address in Underwood, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Underwood averages can't show:
We read public map data around Underwood — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Underwood average
How we know this about Underwood
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Underwood’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Underwood
When does frost risk typically end in Underwood?
The last hard freeze (28°F) in Underwood typically lands around Apr 24, 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 15.
When is the first frost in Underwood?
The first hard freeze (28°F) in Underwood typically arrives around Oct 13, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 29, so the watching starts about Sep 13 — about 172 days after the spring freeze cleared.
How long is the growing season in Underwood?
Measured between 28°F hard freezes, Underwood sees about 172 frost-free days — roughly Apr 24 through Oct 13, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 15 to Sep 29, about 137 days.
Is the soil safe to grow vegetables in Underwood?
The federal record around Underwood shows 182 documented sites, mostly Underground Storage Tanks entries (63), the nearest Underground Storage Tanks record about 0.4 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.
How do I protect my plants from frost in Underwood?
From about Sep 13 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 13 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 13. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Underwood's scale — its 4a band and its 172-day season. Your yard writes its own version of Underwood's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Underwood’s own scale
6 of the readings below were taken at Underwood's own scale — its own ~172-day season between 28°F freezes, the 376 acres it covers and 182 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Underwood's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Underwood's own 28°F hard-freeze dates, about Apr 24 and Oct 13 and the ~172-day span between themNOAA 1991–2020 Climate Normals
- 182 documented contamination sites on the federal record near Underwood, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- Underwood's boundary and the 376 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 ecoregion at Underwood's own centroid, the North Central Hardwood ForestsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Underwood's 376 acres read through its county's SSURGO summaryfrom Otter Tail County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Otter Tail County
- The growing challenges every Minnesota grower plans around — written at state scale, so they stay on the state guidefrom Minnesota
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Otter Tail County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Underwood's 376 acreswhy one lot differs from the next →
- Which side of Underwood you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 376 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.4 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Underwood-wide figureread your own land →
More in Minnesota
Wider growing context
What grows across MinnesotaUnderwood sits outside our named growing regions, so Minnesota as a whole is its closest context here.
Nearby growing guides