The Upper Peninsula spans USDA hardiness zones 4a-5b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Michigan's coldest, shortest-season growing country. The 15 counties north of the Straits of Mackinac sit in USDA zones 4a-5b — from Iron and Gogebic at 4a to the Lake Superior shore at 5b — with frost-free windows running from roughly 126 days at Iron to the 170s-180s along the moderated lakeshore (Keweenaw ~176, Marquette ~172, Alger ~189). That is a fundamentally different regime than the 200+ day, zone-6/7 orchard belt of southern Lower Michigan (Berrien ~223, Allegan ~217): here the Lake Superior lake-effect snowbelt, late-May last frosts, and a boreal Northern Lakes & Forests landscape select for a short-season, cold-hardy crop list — brassicas, roots, potatoes, hardy greens, and cold-tolerant berries over the long-season warm crops that thrive downstate. A curated destination for growers who need to plan around 4a-5b winters and a season that can be barely four months long. Reliable performers under these conditions include cherry, blueberry, apple, and asparagus; what your own ground favors still comes down to its soil, sun, and drainage.
The Upper Peninsula spans Michigan.
Your yard isn't all of the Upper Peninsula.
The Upper Peninsula spans USDA zones 4a-5b, but your parcel sits in exactly one — and slope, tree cover, and low spots nudge it further. 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 Upper Peninsula — soil, climate, flood, and parcel records. How we handle your address.
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The Upper Peninsula — the short answer
The Upper Peninsula: USDA zones 4a-5b, 126–189 frost-free days depending where in it you stand, in Michigan.
- USDA zones
- 4a-5b
- USDA PHZM 2023, aggregated over the footprint
- Shortest season here
- 126 days
- NOAA Regional Climate Centers ACIS, 1991-2020 — Iron County
- Counties
- 15
- US Census TIGER/Line 2025
- Region type
- County cluster
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. The season figure is this region's own record, measured across its 15 member counties, not a state or national average.
Hardiness Zone Range
The Upper Peninsula is not one growing season
One answer for the Upper Peninsula averages 15 counties whose growing seasons are 63 days apart — from 126 frost-free days in Iron County to 189 in Alger County. That is the same region, measured the same way, in the same years. Which end of it your land sits nearer decides what finishes before the first hard freeze.
The middle half of 15 counties runs 149–166 days, with a median of 159 days — a 63-day span end to end.
Measured across 15 member counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020. A member with no own record is absent from the range rather than counted as zero — nothing here is interpolated to the region. Your own site sits somewhere inside this range; a parcel report resolves where.
Where the line runs inside the Upper Peninsula
The middle half of the Upper Peninsula runs 149–166 frost-free days, and 8 of its 15 counties sit outside that — 4 on the short side, 4 on the long. A regional planting date describes the middle well and the ends poorly, which is worth knowing before you follow one.
Under 149 frost-free days
4 counties
- Iron County · 126 days
- Luce County · 134 days
- Dickinson County · 147 days
3 of 4 shown
The end of the region that sets the planting calendar — start seed indoors here and the season stretches to meet the crop.
149–166 frost-free days
7 counties
0 of 7 shown
The middle half of the region, and the part a single regional season describes well.
Over 166 frost-free days
4 counties
- Alger County · 189 days
- Keweenaw County · 176 days
- Marquette County · 172 days
3 of 4 shown
Long enough for a second succession of a quick crop after the first comes out.
Each county is placed by its OWN 28°F frost-free normal (NOAA Regional Climate Centers ACIS, 1991-2020), the same figure its own guide page publishes. Elevation, slope and cold-air drainage move a site within its county as well — which is the part only your address resolves.
What Grows in the Upper Peninsula
Plants matched to the Upper Peninsula's USDA zones 4a-5b, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of the Upper Peninsula
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets the Upper Peninsula’s USDA zones 4a-5b — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground across the Upper Peninsula
The USDA soil survey maps this ground county by county. These are those records weighted by land area across 15 member counties — this region’s own profile, not a state figure.
The ground is predominantly Spodosols, at 54% of mapped acres, followed by Histosols (20%), Alfisols (11%) and Inceptisols (8%). Seven soil orders appear somewhere inside the footprint, which is the honest reason a regional soil answer only goes so far. The most extensive named soils are Kalkaska, Gogebic, and Rubicon.
22% of those acres are well drained, and another 20% moderately well drained, 19% very poorly drained. Topsoil pH runs 4.3–6.7 between the lowest and the highest county on record. 4% of the footprint is classed prime farmland.
Soil order
Spodosols
Drainage
Well drained
Topsoil pH
4.3–6.7
Hydric soils
32%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. Schoolcraft County holds the most wetland ground here, at 50% — soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Upper Peninsula
The soil survey reads this ground county by county, and the readings above are those records summed across the Upper Peninsula. Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records22% of the mapped acres across the Upper Peninsula are well drained — ground that drains quickly. That is area-weighted across all 15 of its mapped counties.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
From county recordsTopsoil across the Upper Peninsula runs pH 4.3–6.7 — acidic in 14 of its 15 counties.
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
Wet ground
From county recordsAbout 32% of the ground across the Upper Peninsula is mapped as hydric — wetland — soil. Schoolcraft County carries the most, at 50%.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Safe to Grow Here?
What the federal record shows across the Upper Peninsula — and how to grow with it.
Across the Upper Peninsula's 15 counties the federal record holds 4,229 documented sites, mostly Underground Storage Tanks (1,930), Brownfields (1,051) and Nitrate (658). The heaviest single county is Marquette County, with 806.
That is a regional count, not a reading of any one lot — proximity to a documented site is information, not a diagnosis. Open the map outlined to the Upper Peninsula to see which records sit where you actually grow.
Sources Checked
Summed across the 15 counties in the Upper Peninsula
A note from Gnorman
What an experienced grower watches for around here
In and around the Upper Peninsula, two things run higher than the national average across the 15 counties in the Upper Peninsula — Mining (433 sites) and Superfund (81 sites). That's not a problem with your land — it's information about it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside the Upper Peninsula
Everything above resolves to the Upper Peninsula as a whole — a footprint whose own counties record seasons 63 days apart, and hardiness across zones 4a-5b. Your parcel sits at one point in that range, not in the middle of it. 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 region 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 regional average.
Your Lot vs the Upper Peninsula Average
Upper Peninsula Average
- ●USDA Zones 4a-5b, averaged across Upper Peninsula
- ●One soil character for all of Upper Peninsula
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Upper Peninsula's 4a-5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Upper Peninsula
Pull a site-specific report for your exact address in the Upper Peninsula — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Upper Peninsula averages can't show:
We read public map data around The Upper Peninsula — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Upper Peninsula average
How we know this about the Upper Peninsula
The boundary: a cluster of neighboring counties. Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the counties inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about the Upper Peninsula
What hardiness zone is the Upper Peninsula?
The Upper Peninsula spans USDA hardiness zones 4a-5b, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's counties. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
How long is the growing season in the Upper Peninsula?
Measured between 28°F hard freezes, the Upper Peninsula's counties mostly run 149 to 166 frost-free days, median 159 (NOAA Regional Climate Centers ACIS, 1991–2020, over 15 member counties). That 17-day spread is the honest read — no single season describes 15 counties, and each county guide below carries its own.
When does frost risk end in the Upper Peninsula?
Across the Upper Peninsula, the middle half of member counties see their last 28°F hard freeze between May 7 and May 12 (median May 8), and their first fall freeze between Oct 7 and Oct 18. Those are hard freezes, not the last light frost: tender transplants wait for about May 29, and elevation decides which end of a 5-day spread you garden in.
What grows well in the Upper Peninsula?
The Upper Peninsula's conditions suit plants such as Cherry, Blueberry, Apple, Asparagus, White Pine. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is the Upper Peninsula defined?
The Upper Peninsula is defined here as a curated cluster of 15 neighboring counties that share a growing character. Growing regions have no official boundary, so this footprint is our published one — every county in it is named on this page.
Which states does the Upper Peninsula cover?
The Upper Peninsula spans Michigan. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Northern Lower Michigan ("Up North"), Metro Detroit & Southeast Michigan, Fruit Ridge / West Michigan, Southwest Michigan Wine Coast, Michigan Thumb, and Leelanau & Old Mission Peninsulas share at least one state with the Upper Peninsula. Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at the Upper Peninsula’s own scale
6 of the readings below were taken at the Upper Peninsula's own scale — the zone 4a-5b band across its footprint, a median 159-day season across its 15 counties and 4,229 documented federal contamination records across its 15 counties, 806 of them in Marquette County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 4a-5b aggregated across all 15 counties in the footprintUSDA PHZM 2023
- The boundary itself — the 15 counties this region is curated fromGrowable Ground subregion registry
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The 28°F season across the footprint — the middle half of its 15 counties run 149 to 166 frost-free days, median 159NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 4,229 documented federal contamination records across its 15 counties, 806 of them in Marquette County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 54% Spodosols, topsoil pH 4.3–6.7, area-weighted across its 15 mapped countiesUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 4a-5bfrom Michigan
What this page can’t tell you
- Which end of the 17-day range your ground sits at — 149 days at one extreme, 166 at the other, decided mostly by elevationfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore the Upper Peninsula
State growing guides
Counties in this region
Other growing regions across Michigan
Up North's interior high plains are Michigan's cold heart: uniformly USDA zone 5a with a short ~145-157-day frost-free season on the sandy jack-pine outwash around Grayling, Gaylord, and Cadillac — a full hardiness zone colder and roughly 40-60 growing days shorter than the lake-warmed Leelanau/Old Mission cherry tip just west (zone 6b, ~176-210 days). Here the droughty, acidic outwash sands and pronounced overnight cold-air pooling make season length and cold-hardiness — not summer heat — the binding constraints on what you can grow.
Michigan's warm southeast corner — and the only captured pocket east of the state's Lake Michigan fruit belt. The Monroe–Macomb–Wayne core sits in zone 6b with roughly 203–207 frost-free days, its springs pulled early and its summers pushed hot by the Detroit River, Lake Erie, and the city's urban heat island; the Ann Arbor and Livingston western edge runs a touch cooler at 6a. A different climate engine than the deep-water cherry country up northwest, and the last frost lands about two weeks earlier.
West Michigan's "Ridge" apple country north of Grand Rapids — an elevated clay-loam moraine moderated by nearby Lake Michigan, spanning USDA zones 5b to 6b and roughly 160 to 207 frost-free days across Kent, Newaygo, Muskegon, and Ottawa counties.
The Lake Michigan Shore AVA — established by the TTB in 1983 (27 CFR §9.130) — makes Southwest Michigan one of the Midwest's oldest federally recognized wine regions, and its four counties (Berrien, Van Buren, Cass, and Allegan) span USDA zones 6a–7a with roughly 207 to 223 frost-free days.
Michigan's Thumb — Huron, Sanilac, and Tuscola counties, the peninsula reaching into Lake Huron between Saginaw Bay and the open lake — sits entirely in USDA hardiness zone 6a, with a frost-free season running roughly 185 to 200 days across the three counties.
Two narrow Lake Michigan peninsulas where deep water holds off spring and fall frost — the heart of Michigan's tart-cherry and cool-climate wine country.