Doniphan County, in Kansas, sits in USDA hardiness zone 6a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
On paper, cabbage, hazelnut, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Doniphan County holds more than one microclimate.
Soils and elevations shift across Doniphan 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 Doniphan County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Doniphan County — the short answer
Doniphan County, Kansas: USDA zone 6a, about 208 days between hard freezes, across 252K acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 5
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 30
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~208
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 252K 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 Doniphan County's average, not your lot's — a low corner or a tree line moves it. Against Doniphan County's 208-day season, see what your own ground reads.
Heat in Doniphan County
Across a year, Doniphan County accumulates about 3,523 growing degree days above 50°F, about 310 fewer than the middle Kansas county — ahead of 21 of Kansas’s 105 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 Doniphan County
Across Doniphan County, the ground is predominantly Inceptisols, where Contrary, Palermo, and Monona are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 6.1–6.5, slightly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Inceptisols
Drainage
Well drained
Prime farmland
15%
Hydric soils
1%
Soil still varies lot by lot — soil types explained.
How the ground varies across Doniphan County
The USDA soil survey maps 77% of Doniphan County as well drained — but another 22% drains differently: 7% somewhat excessively drained, 7% moderately well drained.
Contrary is the most extensive named soil at 23% of mapped acres, then Palermo (8%) and Monona (7%).
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 Doniphan County
Each reading below is measured for Doniphan 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 Doniphan County are well drained, in hydrologic group B — 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 Doniphan County runs about pH 6.1–6.5, 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
MeasuredDoniphan County runs about 208 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredDoniphan 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 Doniphan County is in
Doniphan 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 Doniphan County
We scored all 1,086 plants against Doniphan County's own USDA zone 6a and its own 208-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 Kansas profile.
Is it too late to plant in Doniphan 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 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 30 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
What gets applied to farmland in Doniphan County
USGS estimates 207,712 lb of Glyphosate on Doniphan County farmland in 2019, its largest by weight, ahead of Atrazine (158,965 lb) and Metolachlor & Metolachlor-s (100,167 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 Doniphan County — and how to grow with it.
We checked the federal record across Doniphan County — 192 documented sites across 6 of the 9 source types we track.
The most significant on record: 9 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
The federal record across Doniphan County is a modest one — a typical footprint for a growing area. Nothing here calls for alarm; it's worth knowing which recorded sites sit closest to where you grow, and each one on the map carries its type and location. If one turns out to be a near neighbor, a one-time soil test settles the question.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Doniphan County
Closest first, across Doniphan County. Listing isn't leaking, and distance isn't exposure.
- 03S 20E 12DDB 01Nitrate · 1.7 mi
- 03S 20E 16DCB 01Nitrate · 1.8 mi
- DAVIES OIL CO INCUnderground Storage Tanks · 2.3 mi
- NEUMANN'SUnderground Storage Tanks · 2.3 mi
- 03S 20E 03AAA 01Nitrate · 2.6 mi
- KANSAS DEPT OF TRANSPORTATIONUnderground Storage Tanks · 2.6 mi
- USD #429Underground Storage Tanks · 2.7 mi
- 03S 21E 06BCC 01Nitrate · 2.8 mi
- ENGEMANN DRAINAGE CO INCUnderground Storage Tanks · 2.9 mi
- 03S 21E 06DDC 01Nitrate · 3.0 mi
- BURBRIDGE SERVICEUnderground Storage Tanks · 3.0 mi
- TROY FAST LANEUnderground Storage Tanks · 3.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Doniphan 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 Doniphan County.
Total Sites
192
across Doniphan County
Risk Level
Moderate
Highest-severity
9 Toxics Release Inventory facilities
Sources Checked
across Doniphan County
Severity Distribution
across Doniphan County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Doniphan County, Nitrate runs higher than the national average — 128 sites across Doniphan County. That's not a problem with your land — it's information about 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 Doniphan 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 Doniphan County average
Your land is one point inside Doniphan County
Everything above resolves to Doniphan County as a whole — one PHZM band and one county frost record, read across 252K 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 Doniphan County Average
Doniphan County Average
- ●USDA Zones 6a, averaged across Doniphan County
- ●One soil character for all of Doniphan County
- ●Frost dates read at Doniphan County's scale: Apr 5 to Oct 30
YOUR Parcel
- ✓Your exact zone, not Doniphan County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Doniphan County
Pull a site-specific report for your exact address in Doniphan County, Kansas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Doniphan County averages can't show:
We read public map data around Doniphan County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Doniphan County average
How we know this about Doniphan 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 Doniphan County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Doniphan County
When does frost risk typically end in Doniphan County?
The last hard freeze (28°F) in Doniphan County typically lands around Apr 5, 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 Apr 26.
How long is the growing season in Doniphan County?
Measured between 28°F hard freezes, Doniphan County sees about 208 frost-free days — roughly Apr 5 through Oct 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 26 to Oct 16, about 173 days.
Is the soil safe to grow vegetables in Doniphan County?
The federal record around Doniphan County shows 192 documented sites, mostly Nitrate entries (128), the nearest Nitrate record about 1.7 miles 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.
Everything above is measured at Doniphan County's scale — its 6a band and its 208-day season. Your yard writes its own version of Doniphan 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 Kansas's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Doniphan County’s own scale
8 of the readings below were taken at Doniphan County's own scale — its own ~208-day span between 28°F freezes, the 3 most extensive soil series mapped here and 192 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Doniphan County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Doniphan County's own 28°F hard-freeze dates and its ~208-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Doniphan CountyUSDA NRCS SSURGO
- 192 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 1.7 miles outFederal environmental registers
- Doniphan County's boundary and the 251,824 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~208-day seasonGrowable Ground crop-matching engine
- Doniphan County sitting wholly inside the Western Corn Belt PlainsUS EPA Level III Ecoregions
- Which agricultural compounds go onto Doniphan County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Kansas grower plans around — written at state scale, so they stay on the state guidefrom Kansas
What this page can’t tell you
- How the season shifts across Doniphan County — the ~208 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 Doniphan County's 251,824 acreswhy one lot differs from the next →
- Which of those 192 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 Doniphan Countyread your own land →