Mackinac County, in Michigan, sits in USDA hardiness zone 5a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
On paper, cabbage, cranberry, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Mackinac County lies within the Upper Peninsula — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Mackinac County holds more than one microclimate.
Soils and elevations shift across Mackinac County, so your frost dates and drainage aren't the county average. 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 Mackinac County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Mackinac County — the short answer
Mackinac County, Michigan: USDA zone 5a, about 151 days between hard freezes, across 654K acres.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 13
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 11
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~151
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 654K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 5a is Mackinac County's average, not your lot's — a low corner or a tree line moves it. Against Mackinac County's 151-day season, see what your own ground reads.
Heat in Mackinac County
Across a year, Mackinac County accumulates about 1,496 growing degree days above 50°F, about 604 fewer than the middle Michigan county — ahead of 8 of Michigan’s 83 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Mackinac County
Across Mackinac County, the ground is predominantly Spodosols, where Wallace, Lupton, and Carbondale are the most extensive named soil series. The soil is generally very poorly drained with a sand surface. Topsoil pH runs about 5.1–6.2, moderately acidic. Rainfall drains through hydrologic group A/D soils.
Soil order
Spodosols
Drainage
Very poorly drained
Prime farmland
2%
Hydric soils
43%
Soil still varies lot by lot — soil types explained.
How the ground varies across Mackinac County
The USDA soil survey maps 26% of Mackinac County as very poorly drained — but another 67% drains differently: 23% well drained, 14% somewhat poorly drained.
Wallace is the most extensive named soil at 8% of mapped acres, then Lupton (7%) and Carbondale (5%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Mackinac County
Each reading below is measured for Mackinac County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Mackinac County are very poorly drained, in hydrologic group A/D — ground that sheds water slowly.
Beds can stay saturated for days after heavy rain, and the roots of most vegetables, berries, and fruit trees suffocate or rot in soil that never drains.
Raised beds or mounded rows lift roots above the wet zone; choose water-tolerant crops for the lowest spots.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Mackinac County runs about pH 5.1–6.2, on the acidic side.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Season length
MeasuredMackinac County runs about 151 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
MeasuredMackinac County sits in USDA hardiness zone 5a.
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 Mackinac County is in
Mackinac County sits in the Northern Lakes and Forests — EPA Level III, inside the wider Northern Forests. One consistent ecological setting across the whole county.
What Grows in Mackinac County
We scored all 1,086 plants against Mackinac County's own USDA zone 5a and its own 151-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Michigan profile.
Is it too late to plant in Mackinac County?
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 Apr 15; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 11 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
Documented around Mackinac County
- monarch butterfly297 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Mackinac County
USGS estimates 2,459 lb of Glyphosate on Mackinac County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (1,528 lb) and Metolachlor-s (1,228 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Mackinac County — and how to grow with it.
We checked the federal record across Mackinac County — 178 documented sites across 4 of the 9 source types we track.
The most significant on record: 39 brownfield sites. Former commercial or industrial land where legacy contamination may persist.
The federal record across Mackinac County is a modest one — a typical footprint for a growing area. Nothing here calls for alarm; it's worth knowing which recorded sites sit closest to where you grow, and each one on the map carries its type and location. If one turns out to be a near neighbor, a one-time soil test settles the question.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Mackinac County
Closest first, across Mackinac County. Listing isn't leaking, and distance isn't exposure.
- Rexten Country Store IncUnderground Storage Tanks · 0.7 mi
- GRAYMONT (UP) LLCBrownfields · 2.7 mi
- DnrUnderground Storage Tanks · 3.5 mi
- 43N 09W 13DDDA01 MACKINAC CO (BLACK R CAMPGROUND)Nitrate · 4.5 mi
- Mdot Right of WayUnderground Storage Tanks · 5.4 mi
- Emmet Vallier & CoUnderground Storage Tanks · 6.1 mi
- FAMILY DOLLAR STORESBrownfields · 6.1 mi
- GREAT LAKES GAS TRANSMISSION STATION #10Brownfields · 7.8 mi
- MI DEPT/NATURAL RESOURCES AND ENVIRONMENTBrownfields · 8.5 mi
- Beaudoins Marathon ServiceUnderground Storage Tanks · 8.7 mi
- Kings ShellUnderground Storage Tanks · 8.7 mi
- Rexton GarageUnderground Storage Tanks · 8.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Mackinac County'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 Mackinac County.
Sources Checked
across Mackinac County
Severity Distribution
across Mackinac County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mackinac County, Underground Storage Tanks runs higher than the national average — 124 sites across Mackinac County. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Mackinac County
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 Mackinac County average
Your land is one point inside Mackinac County
Everything above resolves to Mackinac County as a whole — one PHZM band and one county frost record, read across 654K 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 county 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 county average.
Your Lot vs the Mackinac County Average
Mackinac County Average
- ●USDA Zones 5a, averaged across Mackinac County
- ●One soil character for all of Mackinac County
- ●Frost dates read at Mackinac County's scale: May 13 to Oct 11
YOUR Parcel
- ✓Your exact zone, not Mackinac County's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Mackinac County
Pull a site-specific report for your exact address in Mackinac County, Michigan — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mackinac County averages can't show:
We read public map data around Mackinac County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mackinac County average
How we know this about Mackinac County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Mackinac County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Mackinac County
When does frost risk typically end in Mackinac County?
The last hard freeze (28°F) in Mackinac County typically lands around May 13, 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 Jun 3.
How long is the growing season in Mackinac County?
Measured between 28°F hard freezes, Mackinac County sees about 151 frost-free days — roughly May 13 through Oct 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 3 to Sep 27, about 116 days.
Is the soil safe to grow vegetables in Mackinac County?
The federal record around Mackinac County shows 178 documented sites, mostly Underground Storage Tanks entries (124), the nearest Underground Storage Tanks record about 0.7 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.
Everything above is measured at Mackinac County's scale — its 5a band and its 151-day season. Your yard writes its own version of Mackinac County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Michigan's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Mackinac County’s own scale
9 of the readings below were taken at Mackinac County's own scale — its own ~151-day span between 28°F freezes, the 3 most extensive soil series mapped here and 178 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Mackinac County's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Mackinac County's own 28°F hard-freeze dates and its ~151-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Mackinac CountyUSDA NRCS SSURGO
- 178 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 0.7 miles outFederal environmental registers
- Mackinac County's boundary and the 654,002 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~151-day seasonGrowable Ground crop-matching engine
- Mackinac County sitting wholly inside the Northern Lakes and ForestsUS EPA Level III Ecoregions
- Open occurrence records documented in Mackinac County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Mackinac County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Michigan grower plans around — written at state scale, so they stay on the state guidefrom Michigan
What this page can’t tell you
- How the season shifts across Mackinac County — the ~151 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Mackinac County's 654,002 acreswhy one lot differs from the next →
- Which of those 178 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Mackinac Countyread your own land →