Owosso, Michigan, sits in USDA hardiness zone 6a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
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 Owosso, 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 Owosso 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 Owosso — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Owosso — the short answer
Owosso, Michigan: USDA zone 6a, about 189 days between hard freezes, across 3K 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 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~189
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 3K 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 Owosso's average, not your lot's — a low corner or a tree line moves it. Against Owosso's 189-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Owosso
Each reading below is measured for Owosso itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredOwosso runs about 189 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
MeasuredOwosso 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 Owosso is in
Owosso sits in the Southern Michigan/Northern Indiana Drift Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Owosso's own centroid rather than borrowed from Shiawassee County.
What Grows in Owosso
Every plant below cleared Owosso's own zone 6a and its 189-day season. Each card opens that plant's Michigan profile. How we score.
Is it too late to plant in Owosso?
For most of the year, no — what changes is which crops still fit the days remaining. 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 26 — 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.
Documented around Owosso
Survey cells within 31 miles of Owosso checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 52 miles off. What to watch for.
What's on the federal record near Owosso
Closest first, within ~10 miles of Owosso. Listing isn't leaking, and distance isn't exposure.
- Berger & CoUnderground Storage Tanks · 500 ft
- Lee L. Woodard, IncUnderground Storage Tanks · 700 ft
- CROWN LEISURE PRODUCTSToxics Release Inventory · 700 ft
- Clark -OwossoUnderground Storage Tanks · 800 ft
- Stechschulte Gas & Oil Co IncUnderground Storage Tanks · 900 ft
- Lyle ElliottUnderground Storage Tanks · 950 ft
- Central TransportUnderground Storage Tanks · 950 ft
- Owosso Public Works GarageUnderground Storage Tanks · 950 ft
- CONSUMERS ENERGY COBrownfields · 950 ft
- Fire DepartmentUnderground Storage Tanks · 1100 ft
- Reeves Wheel AlignmentUnderground Storage Tanks · 1100 ft
- REEVES WHEEL ALIGNMENTBrownfields · 1100 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Owosso'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 Owosso.
Total Sites
271
within ~10 miles of Owosso
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Owosso
Severity Distribution
within ~10 miles of Owosso
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Owosso, Toxics Release Inventory runs higher than the national average — 29 sites within ~10 miles of Owosso. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Owosso
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 Owosso average
Your land is one point inside Owosso
Everything above resolves to Owosso as a whole — one PHZM band and one 28°F frost record, read across 3K 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 Owosso Average
Owosso Average
- ●USDA Zones 6a, averaged across Owosso
- ●One soil character for all of Owosso
- ●Frost dates read at Owosso's scale: Apr 20 to Oct 26
YOUR Parcel
- ✓Your exact zone, not Owosso's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Owosso
Pull a site-specific report for your exact address in Owosso, Michigan — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Owosso averages can't show:
We read public map data around Owosso — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Owosso average
How we know this about Owosso
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 Owosso’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 Owosso
When does frost risk typically end in Owosso?
The last hard freeze (28°F) in Owosso 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 Owosso?
The first hard freeze (28°F) in Owosso typically arrives around Oct 26, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 12, so the watching starts about Sep 26 — about 189 days after the spring freeze cleared.
How long is the growing season in Owosso?
Measured between 28°F hard freezes, Owosso sees about 189 frost-free days — roughly Apr 20 through Oct 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 11 to Oct 12, about 154 days.
Is the soil safe to grow vegetables in Owosso?
The federal record around Owosso is a meaningful one — 271 documented sites, mostly Underground Storage Tanks entries (133), the nearest Underground Storage Tanks record under a tenth of a mile 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 Owosso?
From about Sep 26 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 26 (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 26. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Owosso's scale — its 6a band and its 189-day season. Your yard writes its own version of Owosso'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 Owosso’s own scale
7 of the readings below were taken at Owosso's own scale — its own ~189-day season between 28°F freezes, the 3,359 acres it covers and 271 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Owosso's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Owosso's own 28°F hard-freeze dates, about Apr 20 and Oct 26 and the ~189-day span between themNOAA 1991–2020 Climate Normals
- 271 documented contamination sites on the federal record near Owosso, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Owosso's boundary and the 3,359 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~189-day seasonGrowable Ground crop-matching engine
- The ecoregion at Owosso's own centroid, the Southern Michigan/Northern Indiana Drift PlainsUS EPA Level III Ecoregions
- Lanternfly survey cells around Owosso 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 Owosso's 3,359 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 Owosso's 3,359 acreswhy one lot differs from the next →
- Which side of Owosso you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,359 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Owosso-wide figureread your own land →
More in Michigan
Wider growing context
What grows across MichiganOwosso sits outside our named growing regions, so Michigan as a whole is its closest context here.
Nearby growing guides