Mahaska, Kansas, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Expect cabbage, hazelnut, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Mahaska, 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 Mahaska 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 Mahaska — soil, climate, flood, and parcel records. How we handle your address.
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Mahaska — the short answer
Mahaska, Kansas: USDA zone 6a, about 199 days between hard freezes, across 143 acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 24
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~199
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 143 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 Mahaska's average, not your lot's — a low corner or a tree line moves it. Against Mahaska's 199-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Mahaska
Each reading below is measured for Mahaska itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMahaska runs about 199 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
MeasuredMahaska 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 Mahaska is in
Mahaska sits in the Central Great Plains — EPA Level III, inside the wider Great Plains. That is read at Mahaska's own centroid rather than borrowed from Washington County.
What Grows in Mahaska
Every plant below cleared Mahaska's own zone 6a and its 199-day season. Each card opens that plant's Kansas profile. How we score.
Is it too late to plant in Mahaska?
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 11; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 8 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 24 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Mahaska
Closest first, within ~10 miles of Mahaska. Listing isn't leaking, and distance isn't exposure.
- MAHASKA PROPANE INCUnderground Storage Tanks · 950 ft
- MAHASKA PROPANE, INC-MAHASKA OUnderground Storage Tanks · 1300 ft
- 01S 01W 11AB 01Nitrate · 2.2 mi
- PIERCE GROCERY & CAFEUnderground Storage Tanks · 4.4 mi
- 01S 01W 27BB 01Nitrate · 4.8 mi
- 01S 01W 28AA 01Nitrate · 5.0 mi
- 1N 1E 8AA 1Nitrate · 6.0 mi
- 02S 01E 03AAD 01Nitrate · 6.0 mi
- 01S 01W 33CD 01Nitrate · 6.6 mi
- LEI FLAT VIEW, LLCCAFO · 6.6 mi
- 02S 01W 10BB 01Nitrate · 7.1 mi
- 2N 1E33DAC 1Nitrate · 7.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Mahaska'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 Mahaska.
Total Sites
29
within ~10 miles of Mahaska
Risk Level
Low
Highest-severity
2 concentrated animal feeding operations
Sources Checked
within ~10 miles of Mahaska
Severity Distribution
within ~10 miles of Mahaska
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mahaska, Nitrate runs higher than the national average — 20 sites within ~10 miles of Mahaska. 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 Mahaska
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 Mahaska average
Your land is one point inside Mahaska
Everything above resolves to Mahaska as a whole — one PHZM band and one 28°F frost record, read across 143 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 Mahaska Average
Mahaska Average
- ●USDA Zones 6a, averaged across Mahaska
- ●One soil character for all of Mahaska
- ●Frost dates read at Mahaska's scale: Apr 8 to Oct 24
YOUR Parcel
- ✓Your exact zone, not Mahaska's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Mahaska
Pull a site-specific report for your exact address in Mahaska, Kansas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mahaska averages can't show:
We read public map data around Mahaska — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mahaska average
How we know this about Mahaska
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 Mahaska’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 Mahaska
When does frost risk typically end in Mahaska?
The last hard freeze (28°F) in Mahaska typically lands around Apr 8, 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 29.
When is the first frost in Mahaska?
The first hard freeze (28°F) in Mahaska typically arrives around Oct 24, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 10, so the watching starts about Sep 24 — about 199 days after the spring freeze cleared.
How long is the growing season in Mahaska?
Measured between 28°F hard freezes, Mahaska sees about 199 frost-free days — roughly Apr 8 through Oct 24, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 29 to Oct 10, about 164 days.
Is the soil safe to grow vegetables in Mahaska?
The federal record around Mahaska is light — 29 documented sites across the 9 federal source types we checked, mostly Nitrate entries (20), the nearest Underground Storage Tanks record about 0.2 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Mahaska?
From about Sep 24 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 24 (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 24. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Mahaska's scale — its 6a band and its 199-day season. Your yard writes its own version of Mahaska'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 Mahaska’s own scale
6 of the readings below were taken at Mahaska's own scale — its own ~199-day season between 28°F freezes, the 143 acres it covers and 29 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Mahaska's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Mahaska's own 28°F hard-freeze dates, about Apr 8 and Oct 24 and the ~199-day span between themNOAA 1991–2020 Climate Normals
- 29 documented contamination sites on the federal record near Mahaska, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Mahaska's boundary and the 143 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~199-day seasonGrowable Ground crop-matching engine
- The ecoregion at Mahaska's own centroid, the Central Great PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Mahaska's 143 acres read through its county's SSURGO summaryfrom Washington County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Washington 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 Washington County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Mahaska's 143 acreswhy one lot differs from the next →
- Which side of Mahaska you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 143 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 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 Mahaska-wide figureread your own land →
More in Kansas
Wider growing context
What grows across KansasMahaska sits outside our named growing regions, so Kansas as a whole is its closest context here.
Nearby growing guides