Crawford 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.
Reliable performers under these conditions include cabbage, cranberry, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Crawford County holds more than one microclimate.
Soils and elevations shift across Crawford 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 Crawford County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Crawford County — the short answer
Crawford County, Iowa: USDA zone 5a, about 191 days between hard freezes, across 457K acres.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 12
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 20
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~191
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 457K 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 Crawford County's average, not your lot's — a low corner or a tree line moves it. Against Crawford County's 191-day season, see what your own ground reads.
Heat in Crawford County
Across a year, Crawford County accumulates about 2,747 growing degree days above 50°F, about 3 more than the middle Iowa county — ahead of 50 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 Crawford County
Across Crawford County, the ground is predominantly Inceptisols, where Judson, Ida, and Napier are the most extensive named soil series. The soil is generally well drained with a silty clay loam surface. Topsoil pH runs about 5.8–6.2, moderately acidic. Rainfall drains through hydrologic group C soils.
Soil order
Inceptisols
Drainage
Well drained
Prime farmland
19%
Hydric soils
4%
Soil still varies lot by lot — soil types explained.
How the ground varies across Crawford County
The USDA soil survey maps 91% of Crawford County as well drained — but another 8% drains differently: 4% moderately well drained, 3% somewhat poorly drained.
Judson is the most extensive named soil at 14% of mapped acres, then Ida (6%) and Napier (5%).
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 Crawford County
Each reading below is measured for Crawford 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 Crawford 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 Crawford County runs about pH 5.8–6.2, 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
MeasuredCrawford County runs about 191 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
MeasuredCrawford 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 Crawford County is in
Crawford County sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. One consistent ecological setting across the whole county.
What Grows in Crawford County
We scored all 1,086 plants against Crawford County's own USDA zone 5a and its own 191-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 Crawford County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 15; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 12 (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. 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 Crawford County
- monarch butterfly29 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Crawford County
USGS estimates 397,819 lb of Glyphosate on Crawford County farmland in 2019, its largest by weight, ahead of Acetochlor (156,175 lb) and Metolachlor & Metolachlor-s (127,826 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 Crawford County — and how to grow with it.
We checked the federal record across Crawford County — 274 documented sites across 6 of the 9 source types we track.
The most significant on record: 16 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
There's a meaningful federal record across Crawford 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 Crawford County
Closest first, across Crawford County. Listing isn't leaking, and distance isn't exposure.
- JERRY BOETTJERToxics Release Inventory · 1.2 mi
- CIRCLE B CASHWAYUnderground Storage Tanks · 1.5 mi
- 083N39W03DCAC 1976Denison 7Nitrate · 1.6 mi
- BOMGAARS SUPPLYUnderground Storage Tanks · 1.7 mi
- BC''S AMPRIDE TRUCK PLAZAUnderground Storage Tanks · 1.7 mi
- 083N39W10ABBD 1971Denison 5Nitrate · 1.7 mi
- NO FRILLS SUPER MARKETUnderground Storage Tanks · 1.8 mi
- SMITHFIELD FARMLAND CORP - DENISONBrownfields · 1.8 mi
- SMITHFIELD FARMLAND CORP - DENISONToxics Release Inventory · 1.8 mi
- SOUTH CRAWFORD RECUnderground Storage Tanks · 1.8 mi
- DENISON WATER SUPPLYPFAS · 1.8 mi
- 083N39W02CCAB 08638 1957Nitrate · 1.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Crawford 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 Crawford County.
Total Sites
274
across Crawford County
Risk Level
Elevated
Highest-severity
16 Toxics Release Inventory facilities
Sources Checked
across Crawford County
Severity Distribution
across Crawford County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Crawford County, Nitrate runs higher than the national average — 130 sites across Crawford 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 Crawford 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 Crawford County average
Your land is one point inside Crawford County
Everything above resolves to Crawford County as a whole — one PHZM band and one county frost record, read across 457K 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 Crawford County Average
Crawford County Average
- ●USDA Zones 5a, averaged across Crawford County
- ●One soil character for all of Crawford County
- ●Frost dates read at Crawford County's scale: Apr 12 to Oct 20
YOUR Parcel
- ✓Your exact zone, not Crawford County's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Crawford County
Pull a site-specific report for your exact address in Crawford County, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Crawford County averages can't show:
We read public map data around Crawford County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Crawford County average
How we know this about Crawford 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 Crawford County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Crawford County
When does frost risk typically end in Crawford County?
The last hard freeze (28°F) in Crawford County typically lands around Apr 12, 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 3.
How long is the growing season in Crawford County?
Measured between 28°F hard freezes, Crawford County sees about 191 frost-free days — roughly Apr 12 through Oct 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 3 to Oct 6, about 156 days.
Is the soil safe to grow vegetables in Crawford County?
The federal record around Crawford County is a meaningful one — 274 documented sites, mostly Nitrate entries (130), the nearest Toxics Release Inventory record about 1.2 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 Crawford County's scale — its 5a band and its 191-day season. Your yard writes its own version of Crawford 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 Crawford County’s own scale
9 of the readings below were taken at Crawford County's own scale — its own ~191-day span between 28°F freezes, the 3 most extensive soil series mapped here and 274 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Crawford County's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Crawford County's own 28°F hard-freeze dates and its ~191-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Crawford CountyUSDA NRCS SSURGO
- 274 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Toxics Release Inventory record about 1.2 miles outFederal environmental registers
- Crawford County's boundary and the 457,087 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~191-day seasonGrowable Ground crop-matching engine
- Crawford County sitting wholly inside the Western Corn Belt PlainsUS EPA Level III Ecoregions
- Open occurrence records documented in Crawford County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Crawford 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 Crawford County — the ~191 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 Crawford County's 457,087 acreswhy one lot differs from the next →
- Which of those 274 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 Crawford Countyread your own land →