Corunna, Michigan, sits in USDA hardiness zone 6a — 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, hazelnut, lavender, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Corunna, 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 Corunna 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 Corunna — soil, climate, flood, and parcel records. How we handle your address.
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Corunna — the short answer
Corunna, Michigan: USDA zone 6a, about 188 days between hard freezes, across 2K acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 25
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~188
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 2K 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 6a is Corunna's average, not your lot's — a low corner or a tree line moves it. Against Corunna's 188-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Corunna
Each reading below is measured for Corunna itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCorunna runs about 188 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
MeasuredCorunna sits in USDA hardiness zone 6a.
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 Corunna is in
Corunna sits in the Southern Michigan/Northern Indiana Drift Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Corunna's own centroid rather than borrowed from Shiawassee County.
What Grows in Corunna
Every plant below cleared Corunna's own zone 6a and its 188-day season. Each card opens that plant's Michigan profile. How we score.
Is it too late to plant in Corunna?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 23; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 20 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 25 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
Documented around Corunna
Survey cells within 31 miles of Corunna checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 49 miles off. What to watch for.
What's on the federal record near Corunna
Closest first, within ~10 miles of Corunna. Listing isn't leaking, and distance isn't exposure.
- Shiawassee County Sherirff DeptUnderground Storage Tanks · 900 ft
- Shiawassee County Rd CommissionUnderground Storage Tanks · 1100 ft
- Town TubUnderground Storage Tanks · 1200 ft
- CITGOBrownfields · 1200 ft
- C & J Auto RepairUnderground Storage Tanks · 1300 ft
- Pac PrideUnderground Storage Tanks · 1400 ft
- Corunna Public SchoolsUnderground Storage Tanks · 1800 ft
- STRAUSS TOOL CO INCBrownfields · 2500 ft
- Agri Sales, IncUnderground Storage Tanks · 0.6 mi
- AKRO CORPORATIONToxics Release Inventory · 0.6 mi
- MI DEPT/MILITARY & VETERANS AFFAIRSBrownfields · 0.7 mi
- Ryder Truck Rental IncUnderground Storage Tanks · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Corunna'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 Corunna.
Total Sites
316
within ~10 miles of Corunna
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Corunna
Severity Distribution
within ~10 miles of Corunna
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Corunna, Toxics Release Inventory runs higher than the national average — 31 sites within ~10 miles of Corunna. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Corunna
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 Corunna average
Your land is one point inside Corunna
Everything above resolves to Corunna as a whole — one PHZM band and one 28°F frost record, read across 2K 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 Corunna Average
Corunna Average
- ●USDA Zones 6a, averaged across Corunna
- ●One soil character for all of Corunna
- ●Frost dates read at Corunna's scale: Apr 20 to Oct 25
YOUR Parcel
- ✓Your exact zone, not Corunna's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Corunna
Pull a site-specific report for your exact address in Corunna, Michigan — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Corunna averages can't show:
We read public map data around Corunna — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Corunna average
How we know this about Corunna
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 Corunna’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 Corunna
When does frost risk typically end in Corunna?
The last hard freeze (28°F) in Corunna typically lands around Apr 20, 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 11.
When is the first frost in Corunna?
The first hard freeze (28°F) in Corunna typically arrives around Oct 25, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 11, so the watching starts about Sep 25 — about 188 days after the spring freeze cleared.
How long is the growing season in Corunna?
Measured between 28°F hard freezes, Corunna sees about 188 frost-free days — roughly Apr 20 through Oct 25, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 11 to Oct 11, about 153 days.
Is the soil safe to grow vegetables in Corunna?
The federal record around Corunna is a meaningful one — 316 documented sites, mostly Underground Storage Tanks entries (155), the nearest Underground Storage Tanks record about 0.2 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 Corunna?
From about Sep 25 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 25 (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 25. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Corunna's scale — its 6a band and its 188-day season. Your yard writes its own version of Corunna'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 Corunna’s own scale
7 of the readings below were taken at Corunna's own scale — its own ~188-day season between 28°F freezes, the 2,036 acres it covers and 316 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Corunna's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Corunna's own 28°F hard-freeze dates, about Apr 20 and Oct 25 and the ~188-day span between themNOAA 1991–2020 Climate Normals
- 316 documented contamination sites on the federal record near Corunna, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Corunna's boundary and the 2,036 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~188-day seasonGrowable Ground crop-matching engine
- The ecoregion at Corunna's own centroid, the Southern Michigan/Northern Indiana Drift PlainsUS EPA Level III Ecoregions
- Lanternfly survey cells around Corunna checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Corunna's 2,036 acres read through its county's SSURGO summaryfrom Shiawassee County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Shiawassee County
- The growing challenges every Michigan grower plans around — written at state scale, so they stay on the state guidefrom Michigan
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Shiawassee County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Corunna's 2,036 acreswhy one lot differs from the next →
- Which side of Corunna you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,036 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 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 Corunna-wide figureread your own land →
More in Michigan
Wider growing context
What grows across MichiganCorunna sits outside our named growing regions, so Michigan as a whole is its closest context here.
Nearby growing guides