Isabella County, in Michigan, sits in USDA hardiness zone 6a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
These conditions suit cabbage, hazelnut, lavender, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Isabella County holds more than one microclimate.
Soils and elevations shift across Isabella 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 Isabella County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Isabella County — the short answer
Isabella County, Michigan: USDA zone 6a, about 185 days between hard freezes, across 367K acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 21
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 23
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~185
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 367K 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 6a is Isabella County's average, not your lot's — a low corner or a tree line moves it. Against Isabella County's 185-day season, see what your own ground reads.
Heat in Isabella County
Across a year, Isabella County accumulates about 2,258 growing degree days above 50°F, about 158 more than the middle Michigan county — ahead of 50 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 Isabella County
Across Isabella County, the ground is predominantly Alfisols, where Coloma, Spinks, and Ithaca are the most extensive named soil series. The soil is generally somewhat poorly drained with a loam surface. Topsoil pH runs about 5.9–6.5, slightly acidic. Rainfall drains through hydrologic group C/D soils.
Soil order
Alfisols
Drainage
Somewhat poorly drained
Prime farmland
32%
Hydric soils
23%
Soil still varies lot by lot — soil types explained.
How the ground varies across Isabella County
The USDA soil survey maps 32% of Isabella County as somewhat poorly drained — but another 67% drains differently: 32% well drained, 15% poorly drained.
Coloma is the most extensive named soil at 8% of mapped acres, then Spinks (8%) and Ithaca (8%).
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 Isabella County
Each reading below is measured for Isabella 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 Isabella County are somewhat poorly drained, in hydrologic group C/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 Isabella County runs about pH 5.9–6.5, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredIsabella County runs about 185 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
MeasuredIsabella County 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 Isabella County is in
Isabella County spans 3 EPA Level III ecoregions — Southern Michigan/Northern Indiana Drift Plains (51%), Northern Lakes and Forests (35%) and Huron/Erie Lake Plains (14%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Isabella County
We scored all 1,086 plants against Isabella County's own USDA zone 6a and its own 185-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 Isabella County?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 24; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 21 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 23 — 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 Isabella County
Survey cells within 31 miles of Isabella County checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 106 miles off. What to watch for.
- Japanese beetle1 documented records
- monarch butterfly166 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Isabella County
USGS estimates 64,096 lb of Glyphosate on Isabella County farmland in 2019, its largest by weight, ahead of Atrazine (12,687 lb) and Metolachlor & Metolachlor-s (10,309 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 Isabella County — and how to grow with it.
We checked the federal record across Isabella County — 367 documented sites across 6 of the 9 source types we track.
The most significant on record: 2 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Isabella County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Isabella County
Closest first, across Isabella County. Listing isn't leaking, and distance isn't exposure.
- Ada SmithUnderground Storage Tanks · 1.5 mi
- Murphy Bulldozing & TruckingUnderground Storage Tanks · 2.3 mi
- MRP PROPERTIES CO LLCBrownfields · 2.5 mi
- MT. PLEASANTPFAS · 3.0 mi
- MOUNT PLEASANT, CITY OFPFAS · 3.0 mi
- UNION TOWNSHIPPFAS · 3.0 mi
- Gary House Excavating, IncUnderground Storage Tanks · 3.1 mi
- Alwood NurseryUnderground Storage Tanks · 3.2 mi
- Mt Pleasant Regional CenterUnderground Storage Tanks · 3.3 mi
- SPEEDWAY 8811Brownfields · 3.4 mi
- MEIJER #69 (TRIBAL)Brownfields · 3.5 mi
- Coyne Oil CorpUnderground Storage Tanks · 3.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Isabella 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 Isabella County.
Total Sites
367
across Isabella County
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
across Isabella County
Severity Distribution
across Isabella County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Isabella County, PFAS runs higher than the national average — 3 sites across Isabella County. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Isabella 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 Isabella County average
Your land is one point inside Isabella County
Everything above resolves to Isabella County as a whole — one PHZM band and one county frost record, read across 367K 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 Isabella County Average
Isabella County Average
- ●USDA Zones 6a, averaged across Isabella County
- ●One soil character for all of Isabella County
- ●Frost dates read at Isabella County's scale: Apr 21 to Oct 23
YOUR Parcel
- ✓Your exact zone, not Isabella County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Isabella County
Pull a site-specific report for your exact address in Isabella County, Michigan — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Isabella County averages can't show:
We read public map data around Isabella County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Isabella County average
How we know this about Isabella 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 Isabella County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Isabella County
When does frost risk typically end in Isabella County?
The last hard freeze (28°F) in Isabella County typically lands around Apr 21, 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 12.
How long is the growing season in Isabella County?
Measured between 28°F hard freezes, Isabella County sees about 185 frost-free days — roughly Apr 21 through Oct 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 12 to Oct 9, about 150 days.
Is the soil safe to grow vegetables in Isabella County?
The federal record around Isabella County is a meaningful one — 367 documented sites, mostly Underground Storage Tanks entries (195), the nearest Underground Storage Tanks record about 1.5 miles 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.
Everything above is measured at Isabella County's scale — its 6a band and its 185-day season. Your yard writes its own version of Isabella 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 Isabella County’s own scale
9 of the readings below were taken at Isabella County's own scale — its own ~185-day span between 28°F freezes, the 3 most extensive soil series mapped here and 367 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Isabella County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Isabella County's own 28°F hard-freeze dates and its ~185-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Isabella CountyUSDA NRCS SSURGO
- 367 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 1.5 miles outFederal environmental registers
- Isabella County's boundary and the 366,528 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~185-day seasonGrowable Ground crop-matching engine
- The 3 ecoregions Isabella County spans, Southern Michigan/Northern Indiana Drift Plains the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Isabella County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Isabella 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 Isabella County — the ~185 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 Isabella County's 366,528 acreswhy one lot differs from the next →
- Which of those 367 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 Isabella Countyread your own land →