Unionville, Michigan, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, cabbage, hazelnut, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Unionville, 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 Unionville 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 Unionville — soil, climate, flood, and parcel records. How we handle your address.
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Unionville — the short answer
Unionville, Michigan: USDA zone 6a, about 199 days between hard freezes, across 601 acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~199
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 601 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 Unionville's average, not your lot's — a low corner or a tree line moves it. Against Unionville's 199-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Unionville
Each reading below is measured for Unionville itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredUnionville runs about 199 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
MeasuredUnionville 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 Unionville is in
Unionville sits in the Huron/Erie Lake Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Unionville's own centroid rather than borrowed from Tuscola County.
What Grows in Unionville
Every plant below cleared Unionville's own zone 6a and its 199-day season. Each card opens that plant's Michigan profile. How we score.
Is it too late to plant in Unionville?
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 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 2 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
Documented around Unionville
Survey cells within 31 miles of Unionville checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 72 miles off. What to watch for.
What's on the federal record near Unionville
Closest first, within ~10 miles of Unionville. Listing isn't leaking, and distance isn't exposure.
- Schmidts Motors IncUnderground Storage Tanks · 75 ft
- Village Mini MktUnderground Storage Tanks · 200 ft
- Village Of UnionvilleUnderground Storage Tanks · 600 ft
- Binder StoreUnderground Storage Tanks · 600 ft
- Harlow BedoreUnderground Storage Tanks · 700 ft
- Unionville Elementary SchoolUnderground Storage Tanks · 900 ft
- Mel's SunocoUnderground Storage Tanks · 2000 ft
- Agri Sales, IncUnderground Storage Tanks · 2400 ft
- Senan Abasso - Unionville Quick StopUnderground Storage Tanks · 0.6 mi
- Vanhoost FarmsUnderground Storage Tanks · 1.5 mi
- CONSUMERS ENERGYBrownfields · 2.4 mi
- 15N 09E 30ABDB 04Nitrate · 2.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Unionville'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 Unionville.
Total Sites
85
within ~10 miles of Unionville
Risk Level
Moderate
Highest-severity
2 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Unionville
Severity Distribution
within ~10 miles of Unionville
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Unionville, Underground Storage Tanks runs higher than the national average — 59 sites within ~10 miles of Unionville. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Unionville
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 Unionville average
Your land is one point inside Unionville
Everything above resolves to Unionville as a whole — one PHZM band and one 28°F frost record, read across 601 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 town 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 Unionville Average
Unionville Average
- ●USDA Zones 6a, averaged across Unionville
- ●One soil character for all of Unionville
- ●Frost dates read at Unionville's scale: Apr 17 to Nov 2
YOUR Parcel
- ✓Your exact zone, not Unionville's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Unionville
Pull a site-specific report for your exact address in Unionville, Michigan — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Unionville averages can't show:
We read public map data around Unionville — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Unionville average
How we know this about Unionville
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Unionville’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 town grain anywhere on this page — there is no town-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 Unionville
When does frost risk typically end in Unionville?
The last hard freeze (28°F) in Unionville typically lands around Apr 17, 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 8.
When is the first frost in Unionville?
The first hard freeze (28°F) in Unionville typically arrives around Nov 2, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 19, so the watching starts about Oct 3 — about 199 days after the spring freeze cleared.
How long is the growing season in Unionville?
Measured between 28°F hard freezes, Unionville sees about 199 frost-free days — roughly Apr 17 through Nov 2, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 8 to Oct 19, about 164 days.
Is the soil safe to grow vegetables in Unionville?
The federal record around Unionville shows 85 documented sites, mostly Underground Storage Tanks entries (59), the nearest Underground Storage Tanks record under a tenth of a mile 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.
How do I protect my plants from frost in Unionville?
From about Oct 3 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 2 (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 2. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Unionville's scale — its 6a band and its 199-day season. Your yard writes its own version of Unionville'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 Unionville’s own scale
7 of the readings below were taken at Unionville's own scale — its own ~199-day season between 28°F freezes, the 601 acres it covers and 85 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Unionville's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Unionville's own 28°F hard-freeze dates, about Apr 17 and Nov 2 and the ~199-day span between themNOAA 1991–2020 Climate Normals
- 85 documented contamination sites on the federal record near Unionville, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Unionville's boundary and the 601 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~199-day seasonGrowable Ground crop-matching engine
- The ecoregion at Unionville's own centroid, the Huron/Erie Lake PlainsUS EPA Level III Ecoregions
- Lanternfly survey cells around Unionville 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 Unionville's 601 acres read through its county's SSURGO summaryfrom Tuscola County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Tuscola 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 Tuscola County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Unionville's 601 acreswhy one lot differs from the next →
- Which side of Unionville you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 601 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 Unionville-wide figureread your own land →
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