Jackson County, in Iowa, sits in USDA hardiness zone 5a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
These conditions suit cabbage, cranberry, 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
Jackson County holds more than one microclimate.
Soils and elevations shift across Jackson 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 Jackson County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Jackson County — the short answer
Jackson County, Iowa: USDA zone 5a, about 189 days between hard freezes, across 407K acres.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 14
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 20
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~189
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 407K 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 Jackson County's average, not your lot's — a low corner or a tree line moves it. Against Jackson County's 189-day season, see what your own ground reads.
Heat in Jackson County
Across a year, Jackson County accumulates about 2,599 growing degree days above 50°F, about 145 fewer than the middle Iowa county — ahead of 28 of Iowa’s 99 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 Jackson County
Across Jackson County, the ground is predominantly Alfisols, where Fayette, Nordness, and Downs are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 6.2–6.5, slightly acidic. Rainfall drains through hydrologic group C soils.
Soil order
Alfisols
Drainage
Well drained
Prime farmland
13%
Hydric soils
6%
Soil still varies lot by lot — soil types explained.
How the ground varies across Jackson County
The USDA soil survey maps 77% of Jackson County as well drained — but another 20% drains differently: 10% moderately well drained, 5% poorly drained.
Fayette is the most extensive named soil at 42% of mapped acres, then Nordness (11%) and Downs (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 Jackson County
Each reading below is measured for Jackson 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 Jackson County are well drained, in hydrologic group C — ground that drains quickly.
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
MeasuredTopsoil across Jackson County runs about pH 6.2–6.5, 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
MeasuredJackson County runs about 189 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
MeasuredJackson 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 Jackson County is in
Jackson County spans 2 EPA Level III ecoregions — Western Corn Belt Plains (73%) and Driftless Area (27%). 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 Jackson County
We scored all 1,086 plants against Jackson County's own USDA zone 5a and its own 189-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 Iowa profile.
Is it too late to plant in Jackson 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 17; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 14 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 20 — 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 Jackson County
- monarch butterfly1,410 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Jackson County
USGS estimates 160,414 lb of Glyphosate on Jackson County farmland in 2019, its largest by weight, ahead of Atrazine (113,142 lb) and Acetochlor (66,795 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 Jackson County — and how to grow with it.
We checked the federal record across Jackson County — 263 documented sites across 7 of the 9 source types we track.
The most significant on record: 1 Superfund site (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Jackson County carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Jackson County
Closest first, across Jackson County. Listing isn't leaking, and distance isn't exposure.
- 085N03E22DAA 06141 1953Andrew 1Nitrate · 1.1 mi
- ANDREW HIGH SCHOOLBrownfields · 1.2 mi
- STEVE HUDRLIKUnderground Storage Tanks · 1.2 mi
- ANDREW PHILLIPS 66Underground Storage Tanks · 1.2 mi
- SAND''S SERVICE & REPAIRUnderground Storage Tanks · 1.3 mi
- COUNTRY CORNERSUnderground Storage Tanks · 1.3 mi
- RONS AUTO SALESUnderground Storage Tanks · 1.3 mi
- ANDREW COMMUNITY SCHOOLUnderground Storage Tanks · 1.3 mi
- 085N03E22DDB 00980 Andrew 1 OldNitrate · 1.3 mi
- 085N03E22D AndrewNitrate · 1.3 mi
- 085N03E04 25185 1962Jackson County Care FacilNitrate · 3.3 mi
- CLOOS & SONS INCUnderground Storage Tanks · 4.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Jackson 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 Jackson County.
Sources Checked
across Jackson County
Severity Distribution
across Jackson County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Jackson County, Nitrate runs higher than the national average — 78 sites across Jackson County. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Jackson 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 Jackson County average
Your land is one point inside Jackson County
Everything above resolves to Jackson County as a whole — one PHZM band and one county frost record, read across 407K 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 Jackson County Average
Jackson County Average
- ●USDA Zones 5a, averaged across Jackson County
- ●One soil character for all of Jackson County
- ●Frost dates read at Jackson County's scale: Apr 14 to Oct 20
YOUR Parcel
- ✓Your exact zone, not Jackson County's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Jackson County
Pull a site-specific report for your exact address in Jackson County, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Jackson County averages can't show:
We read public map data around Jackson County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Jackson County average
How we know this about Jackson 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 Jackson County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Jackson County
When does frost risk typically end in Jackson County?
The last hard freeze (28°F) in Jackson County typically lands around Apr 14, 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 5.
How long is the growing season in Jackson County?
Measured between 28°F hard freezes, Jackson County sees about 189 frost-free days — roughly Apr 14 through Oct 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 5 to Oct 6, about 154 days.
Is the soil safe to grow vegetables in Jackson County?
The federal record around Jackson County runs heavier than most — 263 documented sites, mostly Underground Storage Tanks entries (122), the nearest Nitrate record about 1.1 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Everything above is measured at Jackson County's scale — its 5a band and its 189-day season. Your yard writes its own version of Jackson 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 Iowa's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Jackson County’s own scale
9 of the readings below were taken at Jackson County's own scale — its own ~189-day span between 28°F freezes, the 3 most extensive soil series mapped here and 263 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Jackson County's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Jackson County's own 28°F hard-freeze dates and its ~189-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Jackson CountyUSDA NRCS SSURGO
- 263 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 1.1 miles outFederal environmental registers
- Jackson County's boundary and the 407,070 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~189-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Jackson County spans, Western Corn Belt Plains the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Jackson County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Jackson County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Iowa grower plans around — written at state scale, so they stay on the state guidefrom Iowa
What this page can’t tell you
- How the season shifts across Jackson County — the ~189 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 Jackson County's 407,070 acreswhy one lot differs from the next →
- Which of those 263 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 Jackson Countyread your own land →