Port Huron, Michigan, sits in USDA hardiness zone 6b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
The conditions favor cabbage, hazelnut, lavender, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Port Huron, 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 Port Huron 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 Port Huron — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Port Huron — the short answer
Port Huron, Michigan: USDA zone 6b, about 210 days between hard freezes, across 5K acres of city.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 14
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~210
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 5K 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 6b is Port Huron's average, not your lot's — a low corner or a tree line moves it. Against Port Huron's 210-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Port Huron
Each reading below is measured for Port Huron itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredPort Huron runs about 210 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredPort Huron sits in USDA hardiness zone 6b.
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 Port Huron is in
Port Huron sits in the Huron/Erie Lake Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Port Huron's own centroid rather than borrowed from St. Clair County.
What Grows in Port Huron
Every plant below cleared Port Huron's own zone 6b and its 210-day season. Each card opens that plant's Michigan profile. How we score.
Is it too late to plant in Port Huron?
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 17; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 14 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 10 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
Documented around Port Huron
Survey cells within 31 miles of Port Huron checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 51 miles off. What to watch for.
What's on the federal record near Port Huron
Closest first, within ~10 miles of Port Huron. Listing isn't leaking, and distance isn't exposure.
- CLARK OIL COBrownfields · 250 ft
- Admiral Petroleum II LLC #173Underground Storage Tanks · 300 ft
- Shell Port Huron #3Underground Storage Tanks · 750 ft
- PLASTIC PLAQUE PRODUCTS INCBrownfields · 950 ft
- Pine Grove Cleaners, IncUnderground Storage Tanks · 1100 ft
- PINE GROVE CLEANERS INCBrownfields · 1200 ft
- LONDONS FARM DAIRY INCBrownfields · 1300 ft
- Former London Farm DairyUnderground Storage Tanks · 1300 ft
- LONDON'S FARM DAIRYToxics Release Inventory · 1300 ft
- Petes Car CareUnderground Storage Tanks · 1300 ft
- James MossUnderground Storage Tanks · 1600 ft
- METALOR TECHNOLOGIES USABrownfields · 1600 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Port Huron'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 Port Huron.
Total Sites
527
within ~10 miles of Port Huron
Risk Level
Elevated
Highest-severity
4 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Port Huron
Severity Distribution
within ~10 miles of Port Huron
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Port Huron, two things run higher than the national average within ~10 miles of Port Huron — Toxics Release Inventory (45 sites) and PFAS (6 sites). That's not a problem with your land — it's information about it.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Port Huron
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 Port Huron average
Your land is one point inside Port Huron
Everything above resolves to Port Huron as a whole — one PHZM band and one 28°F frost record, read across 5K 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 Port Huron Average
Port Huron Average
- ●USDA Zones 6b, averaged across Port Huron
- ●One soil character for all of Port Huron
- ●Frost dates read at Port Huron's scale: Apr 14 to Nov 10
YOUR Parcel
- ✓Your exact zone, not Port Huron's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Port Huron
Pull a site-specific report for your exact address in Port Huron, Michigan — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Port Huron averages can't show:
We read public map data around Port Huron — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Port Huron average
How we know this about Port Huron
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 Port Huron’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 Port Huron
When does frost risk typically end in Port Huron?
The last hard freeze (28°F) in Port Huron typically lands around Apr 14, 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 5.
When is the first frost in Port Huron?
The first hard freeze (28°F) in Port Huron typically arrives around Nov 10, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 27, so the watching starts about Oct 11 — about 210 days after the spring freeze cleared.
How long is the growing season in Port Huron?
Measured between 28°F hard freezes, Port Huron sees about 210 frost-free days — roughly Apr 14 through Nov 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 5 to Oct 27, about 175 days.
Is the soil safe to grow vegetables in Port Huron?
The federal record around Port Huron is a meaningful one — 527 documented sites, mostly Underground Storage Tanks entries (238), the nearest Brownfields 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 Port Huron?
From about Oct 11 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 Nov 10 (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 Nov 10. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Port Huron's scale — its 6b band and its 210-day season. Your yard writes its own version of Port Huron'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 Port Huron’s own scale
7 of the readings below were taken at Port Huron's own scale — its own ~210-day season between 28°F freezes, the 5,185 acres it covers and 527 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Port Huron's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Port Huron's own 28°F hard-freeze dates, about Apr 14 and Nov 10 and the ~210-day span between themNOAA 1991–2020 Climate Normals
- 527 documented contamination sites on the federal record near Port Huron, the closest Brownfields record under a tenth of a mile out from the town centreFederal environmental registers
- Port Huron's boundary and the 5,185 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~210-day seasonGrowable Ground crop-matching engine
- The ecoregion at Port Huron's own centroid, the Huron/Erie Lake PlainsUS EPA Level III Ecoregions
- Lanternfly survey cells around Port Huron 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 Port Huron's 5,185 acres read through its county's SSURGO summaryfrom St. Clair County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom St. Clair 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 St. Clair County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Port Huron's 5,185 acreswhy one lot differs from the next →
- Which side of Port Huron you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 5,185 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Port Huron-wide figureread your own land →
More in Michigan
Wider growing context
What grows across MichiganPort Huron sits outside our named growing regions, so Michigan as a whole is its closest context here.
Nearby growing guides