Clay County, in Kansas, sits in USDA hardiness zone 6b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Growers here do well with cabbage, hazelnut, lavender, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Clay County holds more than one microclimate.
Soils and elevations shift across Clay 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 Clay County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Clay County — the short answer
Clay County, Kansas: USDA zone 6b, about 211 days between hard freezes, across 413K acres.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 3
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 31
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~211
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 413K 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 6b is Clay County's average, not your lot's — a low corner or a tree line moves it. Against Clay County's 211-day season, see what your own ground reads.
Heat in Clay County
Across a year, Clay County accumulates about 3,846 growing degree days above 50°F, about 13 more than the middle Kansas county — ahead of 54 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 Clay County
Across Clay County, the ground is predominantly Mollisols, where Crete, Muir, and Geary are the most extensive named soil series. The soil is generally moderately well drained with a silty clay loam surface. Topsoil pH runs about 5.7–6.1, moderately acidic. Rainfall drains through hydrologic group C soils.
Soil order
Mollisols
Drainage
Moderately well drained
Prime farmland
68%
Hydric soils
0%
Soil still varies lot by lot — soil types explained.
How the ground varies across Clay County
The USDA soil survey maps 53% of Clay County as moderately well drained — but another 46% drains differently: 41% well drained, 4% somewhat excessively drained.
Crete is the most extensive named soil at 41% of mapped acres, then Muir (9%) and Geary (9%).
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 Clay County
Each reading below is measured for Clay 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 Clay County are moderately well drained, in hydrologic group C — roughly the middle of the drainage range.
This is close to the middle most vegetables prefer: it holds enough water to carry a crop between rains without staying waterlogged. The catch is that a wet spring or a low corner can still tip it soggy.
Plant on the site as-is for most crops, but keep the lowest, slowest-draining beds for moisture-tolerant plantings.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Clay County runs about pH 5.7–6.1, 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
MeasuredClay County runs about 211 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
MeasuredClay County sits in USDA hardiness zone 6b.
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 Clay County is in
Clay County spans 2 EPA Level III ecoregions — Central Great Plains (93%) and Flint Hills (7%). 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 Clay County
We scored all 1,086 plants against Clay County's own USDA zone 6b and its own 211-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 Clay 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 6; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 3 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 31 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
What gets applied to farmland in Clay County
USGS estimates 249,442 lb of Glyphosate on Clay County farmland in 2019, its largest by weight, ahead of Acephate (105,493 lb) and Dicamba (72,188 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 Clay County — and how to grow with it.
We checked the federal record across Clay County — 148 documented sites across 6 of the 9 source types we track.
The most significant on record: 3 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
The federal record across Clay 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 Clay County
Closest first, across Clay County. Listing isn't leaking, and distance isn't exposure.
- CLAY CENTER, CITY OFPFAS · 1.2 mi
- 08S 02E 11ADB 01Nitrate · 2.1 mi
- AIRPORT SERVICE STATIONUnderground Storage Tanks · 2.4 mi
- CLAY CENTER, CITY OFUnderground Storage Tanks · 2.4 mi
- PERFECTION AUTO BODY INCBrownfields · 2.6 mi
- KANSAS DEPT OF TRANSPORTATIONUnderground Storage Tanks · 2.6 mi
- CLAY CENTERBrownfields · 2.6 mi
- TRACTOR SUPPLY STORE #2398Brownfields · 2.6 mi
- KDOT DIST 2 AREA 1 SHOPBrownfields · 2.6 mi
- SHORT STOP #2Underground Storage Tanks · 2.7 mi
- LEISZLER OIL CO INCUnderground Storage Tanks · 2.7 mi
- 08S 02E 02CCA 01Nitrate · 2.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Clay 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 Clay County.
Total Sites
148
across Clay County
Risk Level
Moderate
Highest-severity
3 Toxics Release Inventory facilities
Sources Checked
across Clay County
Severity Distribution
across Clay County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Clay County, two things run higher than the national average across Clay County — CAFO (5 sites) and Nitrate (80 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Clay 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 Clay County average
Your land is one point inside Clay County
Everything above resolves to Clay County as a whole — one PHZM band and one county frost record, read across 413K 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 Clay County Average
Clay County Average
- ●USDA Zones 6b, averaged across Clay County
- ●One soil character for all of Clay County
- ●Frost dates read at Clay County's scale: Apr 3 to Oct 31
YOUR Parcel
- ✓Your exact zone, not Clay County's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Clay County
Pull a site-specific report for your exact address in Clay County, Kansas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Clay County averages can't show:
We read public map data around Clay County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Clay County average
How we know this about Clay 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 Clay County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Clay County
When does frost risk typically end in Clay County?
The last hard freeze (28°F) in Clay County typically lands around Apr 3, 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 24.
How long is the growing season in Clay County?
Measured between 28°F hard freezes, Clay County sees about 211 frost-free days — roughly Apr 3 through Oct 31, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 24 to Oct 17, about 176 days.
Is the soil safe to grow vegetables in Clay County?
The federal record around Clay County shows 148 documented sites, mostly Nitrate entries (80), the nearest PFAS record about 1.2 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 Clay County's scale — its 6b band and its 211-day season. Your yard writes its own version of Clay 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 Clay County’s own scale
8 of the readings below were taken at Clay County's own scale — its own ~211-day span between 28°F freezes, the 3 most extensive soil series mapped here and 148 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Clay County's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Clay County's own 28°F hard-freeze dates and its ~211-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Clay CountyUSDA NRCS SSURGO
- 148 documented contamination sites inside the county boundary, distance-sorted from its center — the closest PFAS record about 1.2 miles outFederal environmental registers
- Clay County's boundary and the 412,990 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~211-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Clay County spans, Central Great Plains the largestUS EPA Level III Ecoregions
- Which agricultural compounds go onto Clay 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 Clay County — the ~211 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 Clay County's 412,990 acreswhy one lot differs from the next →
- Which of those 148 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 Clay Countyread your own land →