Frontenac, Minnesota, sits in USDA hardiness zone 4b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
A short list that earns its place here — cabbage, cranberry, turkish rocket, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Frontenac, 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 Frontenac 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 Frontenac — soil, climate, flood, and parcel records. How we handle your address.
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Frontenac — the short answer
Frontenac, Minnesota: USDA zone 4b, about 187 days between hard freezes, across 1K acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 16
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~187
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 4b is Frontenac's average, not your lot's — a low corner or a tree line moves it. Against Frontenac's 187-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Frontenac
Each reading below is measured for Frontenac itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredFrontenac runs about 187 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
MeasuredFrontenac sits in USDA hardiness zone 4b.
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 Frontenac is in
Frontenac sits in the Driftless Area — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Frontenac's own centroid rather than borrowed from Goodhue County.
What Grows in Frontenac
Every plant below cleared Frontenac's own zone 4b and its 187-day season. Each card opens that plant's Minnesota profile. How we score.
Is it too late to plant in Frontenac?
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 19; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 16 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 20 — 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.
What's on the federal record near Frontenac
Closest first, within ~10 miles of Frontenac. Listing isn't leaking, and distance isn't exposure.
- HERITAGE ACRESBrownfields · 2200 ft
- 408183Nitrate · 1.4 mi
- 104228Nitrate · 1.4 mi
- North Star Asphalt/ Roch Sand & GravelUnderground Storage Tanks · 1.5 mi
- Frontenac StationUnderground Storage Tanks · 1.5 mi
- MDNR FRONTENAC STATE PARKBrownfields · 1.6 mi
- 558288Nitrate · 2.0 mi
- 194168Nitrate · 2.1 mi
- 437892Nitrate · 2.2 mi
- 532081Nitrate · 2.8 mi
- 156923Nitrate · 2.9 mi
- INTERNATIONAL INGREDIENT CORPToxics Release Inventory · 3.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Frontenac'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 Frontenac.
Total Sites
252
within ~10 miles of Frontenac
Risk Level
Elevated
Highest-severity
10 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Frontenac
Severity Distribution
within ~10 miles of Frontenac
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Frontenac, two things run higher than the national average within ~10 miles of Frontenac — CAFO (5 sites) and Nitrate (68 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Frontenac
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 Frontenac average
Your land is one point inside Frontenac
Everything above resolves to Frontenac as a whole — one PHZM band and one 28°F frost record, read across 1K 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 town 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 Frontenac Average
Frontenac Average
- ●USDA Zones 4b, averaged across Frontenac
- ●One soil character for all of Frontenac
- ●Frost dates read at Frontenac's scale: Apr 16 to Oct 20
YOUR Parcel
- ✓Your exact zone, not Frontenac's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Frontenac
Pull a site-specific report for your exact address in Frontenac, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Frontenac averages can't show:
We read public map data around Frontenac — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Frontenac average
How we know this about Frontenac
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Frontenac’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 town grain anywhere on this page — there is no town-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 Frontenac
When does frost risk typically end in Frontenac?
The last hard freeze (28°F) in Frontenac typically lands around Apr 16, 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 7.
When is the first frost in Frontenac?
The first hard freeze (28°F) in Frontenac typically arrives around Oct 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 6, so the watching starts about Sep 20 — about 187 days after the spring freeze cleared.
How long is the growing season in Frontenac?
Measured between 28°F hard freezes, Frontenac sees about 187 frost-free days — roughly Apr 16 through Oct 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 7 to Oct 6, about 152 days.
Is the soil safe to grow vegetables in Frontenac?
The federal record around Frontenac is a meaningful one — 252 documented sites, mostly Underground Storage Tanks entries (103), the nearest Brownfields 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.
How do I protect my plants from frost in Frontenac?
From about Sep 20 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 20 (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 20. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Frontenac's scale — its 4b band and its 187-day season. Your yard writes its own version of Frontenac'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 Frontenac’s own scale
6 of the readings below were taken at Frontenac's own scale — its own ~187-day season between 28°F freezes, the 1,180 acres it covers and 252 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Frontenac's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Frontenac's own 28°F hard-freeze dates, about Apr 16 and Oct 20 and the ~187-day span between themNOAA 1991–2020 Climate Normals
- 252 documented contamination sites on the federal record near Frontenac, the closest Brownfields record about 0.4 miles out from the town centreFederal environmental registers
- Frontenac's boundary and the 1,180 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~187-day seasonGrowable Ground crop-matching engine
- The ecoregion at Frontenac's own centroid, the Driftless AreaUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Frontenac's 1,180 acres read through its county's SSURGO summaryfrom Goodhue County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Goodhue 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 Goodhue County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Frontenac's 1,180 acreswhy one lot differs from the next →
- Which side of Frontenac you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,180 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Frontenac-wide figureread your own land →
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