Isanti County, in Minnesota, sits in USDA hardiness zone 4b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Expect cabbage, cranberry, turkish rocket, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Isanti County holds more than one microclimate.
Soils and elevations shift across Isanti 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 Isanti County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Isanti County — the short answer
Isanti County, Minnesota: USDA zone 4b, about 171 days between hard freezes, across 279K acres.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 26
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 14
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~171
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 279K 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 4b is Isanti County's average, not your lot's — a low corner or a tree line moves it. Against Isanti County's 171-day season, see what your own ground reads.
Heat in Isanti County
Across a year, Isanti County accumulates about 2,179 growing degree days above 50°F, about 86 fewer than the middle Minnesota county — ahead of 32 of Minnesota’s 87 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 Isanti County
Across Isanti County, the ground is predominantly Alfisols, where Zimmerman, Seelyeville, and Lino are the most extensive named soil series. The soil is generally very poorly drained with a fine sand surface. Topsoil pH runs about 5.6–6.1, moderately acidic. Rainfall drains through hydrologic group A/D soils.
Soil order
Alfisols
Drainage
Very poorly drained
Prime farmland
10%
Hydric soils
32%
Soil still varies lot by lot — soil types explained.
How the ground varies across Isanti County
The USDA soil survey maps 27% of Isanti County as very poorly drained — but another 70% drains differently: 23% somewhat excessively drained, 16% well drained.
Zimmerman is the most extensive named soil at 25% of mapped acres, then Seelyeville (10%) and Lino (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 Isanti County
Each reading below is measured for Isanti 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 Isanti 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 Isanti County runs about pH 5.6–6.1, 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
MeasuredIsanti County runs about 171 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
MeasuredIsanti County sits in USDA hardiness zone 4b.
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 Isanti County is in
Isanti County sits in the North Central Hardwood Forests — EPA Level III, inside the wider Eastern Temperate Forests. One consistent ecological setting across the whole county.
What Grows in Isanti County
We scored all 1,086 plants against Isanti County's own USDA zone 4b and its own 171-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 Minnesota profile.
Is it too late to plant in Isanti County?
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 29; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 26 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 14 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
Documented around Isanti County
- monarch butterfly4 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Isanti County
USGS estimates 41,547 lb of Glyphosate on Isanti County farmland in 2019, its largest by weight, ahead of Acetochlor (23,947 lb) and Metolachlor & Metolachlor-s (15,837 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 Isanti County — and how to grow with it.
We checked the federal record across Isanti County — 342 documented sites across 7 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 Isanti 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 Isanti County
Closest first, across Isanti County. Listing isn't leaking, and distance isn't exposure.
- CambridgePFAS · 1.1 mi
- Aircraft Fueling FacilityUnderground Storage Tanks · 1.6 mi
- EC's Corner ExpressUnderground Storage Tanks · 1.6 mi
- Murphy Oil- Spur #6811 Wal-martUnderground Storage Tanks · 1.6 mi
- Wal-mart (murphy Oil) Spur #6525Underground Storage Tanks · 1.6 mi
- Caseys General Store #2155Underground Storage Tanks · 1.6 mi
- Larson CycleUnderground Storage Tanks · 1.6 mi
- Hangar #7Underground Storage Tanks · 1.6 mi
- Forest Lawn & Garden CenterUnderground Storage Tanks · 1.6 mi
- Mike Mueller/cambridge AirportUnderground Storage Tanks · 1.6 mi
- Dr John Laur/cambridge AirportUnderground Storage Tanks · 1.6 mi
- Reds TvUnderground Storage Tanks · 1.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Isanti 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 Isanti County.
Total Sites
342
across Isanti County
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
across Isanti County
Severity Distribution
across Isanti County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Isanti County, Nitrate runs higher than the national average — 98 sites across Isanti County. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Isanti 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 Isanti County average
Your land is one point inside Isanti County
Everything above resolves to Isanti County as a whole — one PHZM band and one county frost record, read across 279K 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 Isanti County Average
Isanti County Average
- ●USDA Zones 4b, averaged across Isanti County
- ●One soil character for all of Isanti County
- ●Frost dates read at Isanti County's scale: Apr 26 to Oct 14
YOUR Parcel
- ✓Your exact zone, not Isanti County's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Isanti County
Pull a site-specific report for your exact address in Isanti County, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Isanti County averages can't show:
We read public map data around Isanti County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Isanti County average
How we know this about Isanti 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 Isanti County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Isanti County
When does frost risk typically end in Isanti County?
The last hard freeze (28°F) in Isanti County typically lands around Apr 26, 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 17.
How long is the growing season in Isanti County?
Measured between 28°F hard freezes, Isanti County sees about 171 frost-free days — roughly Apr 26 through Oct 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 17 to Sep 30, about 136 days.
Is the soil safe to grow vegetables in Isanti County?
The federal record around Isanti County is a meaningful one — 342 documented sites, mostly Brownfields entries (145), the nearest PFAS record about 1.1 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 Isanti County's scale — its 4b band and its 171-day season. Your yard writes its own version of Isanti 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 Minnesota's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Isanti County’s own scale
9 of the readings below were taken at Isanti County's own scale — its own ~171-day span between 28°F freezes, the 3 most extensive soil series mapped here and 342 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Isanti County's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Isanti County's own 28°F hard-freeze dates and its ~171-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Isanti CountyUSDA NRCS SSURGO
- 342 documented contamination sites inside the county boundary, distance-sorted from its center — the closest PFAS record about 1.1 miles outFederal environmental registers
- Isanti County's boundary and the 278,900 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~171-day seasonGrowable Ground crop-matching engine
- Isanti County sitting wholly inside the North Central Hardwood ForestsUS EPA Level III Ecoregions
- Open occurrence records documented in Isanti County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Isanti County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Minnesota grower plans around — written at state scale, so they stay on the state guidefrom Minnesota
What this page can’t tell you
- How the season shifts across Isanti County — the ~171 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 Isanti County's 278,900 acreswhy one lot differs from the next →
- Which of those 342 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 Isanti Countyread your own land →