Grinnell, Kansas, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
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.
Even in Grinnell, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Grinnell lot. 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 Grinnell — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Grinnell — the short answer
Grinnell, Kansas: USDA zone 6a, about 191 days between hard freezes, across 315 acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 14
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 22
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~191
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 315 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 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 Grinnell's average, not your lot's — a low corner or a tree line moves it. Against Grinnell's 191-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Grinnell
Each reading below is measured for Grinnell itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredGrinnell 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
MeasuredGrinnell 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 Grinnell is in
Grinnell sits in the High Plains — EPA Level III, inside the wider Great Plains. That is read at Grinnell's own centroid, and it is not what its county reads: Gove County is mostly Central Great Plains. The wider page above you is answering a different question about different ground.
What Grows in Grinnell
Every plant below cleared Grinnell's own zone 6a and its 191-day season. Each card opens that plant's Kansas profile. How we score.
Is it too late to plant in Grinnell?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. 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 22 — 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 Grinnell
Survey cells within 31 miles of Grinnell checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 574 miles off. What to watch for.
What's on the federal record near Grinnell
Closest first, within ~10 miles of Grinnell. Listing isn't leaking, and distance isn't exposure.
- OSTMEYER, RALPHUnderground Storage Tanks · 650 ft
- BAALMAN & STRUCKHOFF INCUnderground Storage Tanks · 650 ft
- USD #291Underground Storage Tanks · 750 ft
- COOPER OIL COMPANYUnderground Storage Tanks · 1800 ft
- FRONTIER AG. INC. - GRINNELLUnderground Storage Tanks · 0.5 mi
- FRIENDS OF GRINNELL, INCUnderground Storage Tanks · 1.1 mi
- 10S 30W 33CCC 01Nitrate · 2.9 mi
- 10S 30W 33CCB 01Nitrate · 2.9 mi
- 10S 30W 32ADBB01 COS-1187Nitrate · 3.3 mi
- 10S 29W 29ABC 01Nitrate · 3.6 mi
- 10S 30W 14DBD 01Nitrate · 3.8 mi
- 11S 30W 07CB 01Nitrate · 3.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Grinnell'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 Grinnell.
Total Sites
99
within ~10 miles of Grinnell
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Grinnell
Severity Distribution
within ~10 miles of Grinnell
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Grinnell, two things run higher than the national average within ~10 miles of Grinnell — CAFO (4 sites) and Nitrate (68 sites). That's not a problem with your land — it's information about it.
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 Grinnell
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 Grinnell average
Your land is one point inside Grinnell
Everything above resolves to Grinnell as a whole — one PHZM band and one 28°F frost record, read across 315 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 city 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 local average.
Your Lot vs the Grinnell Average
Grinnell Average
- ●USDA Zones 6a, averaged across Grinnell
- ●One soil character for all of Grinnell
- ●Frost dates read at Grinnell's scale: Apr 14 to Oct 22
YOUR Parcel
- ✓Your exact zone, not Grinnell's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Grinnell
Pull a site-specific report for your exact address in Grinnell, Kansas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Grinnell averages can't show:
We read public map data around Grinnell — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Grinnell average
How we know this about Grinnell
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Grinnell’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Grinnell
When does frost risk typically end in Grinnell?
The last hard freeze (28°F) in Grinnell 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.
When is the first frost in Grinnell?
The first hard freeze (28°F) in Grinnell typically arrives around Oct 22, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 8, so the watching starts about Sep 22 — about 191 days after the spring freeze cleared.
How long is the growing season in Grinnell?
Measured between 28°F hard freezes, Grinnell sees about 191 frost-free days — roughly Apr 14 through Oct 22, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 5 to Oct 8, about 156 days.
Is the soil safe to grow vegetables in Grinnell?
The federal record around Grinnell shows 99 documented sites, mostly Nitrate entries (68), the nearest Underground Storage Tanks record about 0.1 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.
How do I protect my plants from frost in Grinnell?
From about Sep 22 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 22 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 22. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Grinnell's scale — its 6a band and its 191-day season. Your yard writes its own version of Grinnell's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Grinnell’s own scale
7 of the readings below were taken at Grinnell's own scale — its own ~191-day season between 28°F freezes, the 315 acres it covers and 99 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Grinnell's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Grinnell's own 28°F hard-freeze dates, about Apr 14 and Oct 22 and the ~191-day span between themNOAA 1991–2020 Climate Normals
- 99 documented contamination sites on the federal record near Grinnell, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Grinnell's boundary and the 315 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~191-day seasonGrowable Ground crop-matching engine
- Grinnell sits in the High Plains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
- Lanternfly survey cells around Grinnell checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Grinnell's 315 acres read through its county's SSURGO summaryfrom Gove County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Gove County
- The growing challenges every Kansas grower plans around — written at state scale, so they stay on the state guidefrom Kansas
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Gove County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Grinnell's 315 acreswhy one lot differs from the next →
- Which side of Grinnell you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 315 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Grinnell-wide figureread your own land →
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