Tonkawa, Oklahoma, sits in USDA hardiness zone 7a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
These conditions suit cabbage, hazelnut, california poppy, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Tonkawa, 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 Tonkawa 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 Tonkawa — soil, climate, flood, and parcel records. How we handle your address.
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Tonkawa — the short answer
Tonkawa, Oklahoma: USDA zone 7a, about 228 days between hard freezes, across 3K acres of city.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 27
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~228
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 3K 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 7a is Tonkawa's average, not your lot's — a low corner or a tree line moves it. Against Tonkawa's 228-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Tonkawa
Each reading below is measured for Tonkawa itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredTonkawa runs about 228 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
MeasuredTonkawa sits in USDA hardiness zone 7a.
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 Tonkawa is in
Tonkawa sits in the Central Great Plains — EPA Level III, inside the wider Great Plains. That is read at Tonkawa's own centroid rather than borrowed from Kay County.
What Grows in Tonkawa
Every plant below cleared Tonkawa's own zone 7a and its 228-day season. Each card opens that plant's Oklahoma profile. How we score.
Is it too late to plant in Tonkawa?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Feb 27; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 27 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 10 — 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's on the federal record near Tonkawa
Closest first, within ~10 miles of Tonkawa. Listing isn't leaking, and distance isn't exposure.
- TONKAWA FOUNDRY INC / TONKAWA FOUNDRYToxics Release Inventory · 2000 ft
- Summers One StopUnderground Storage Tanks · 2100 ft
- Auto Mart - Bernard BuchholzUnderground Storage Tanks · 2400 ft
- B & L FOUNDRY INCToxics Release Inventory · 2500 ft
- GARYS PAINT & BODYBrownfields · 2600 ft
- Farmers Cooperative Assoc.Underground Storage Tanks · 0.6 mi
- Owen Sinclair ServiceUnderground Storage Tanks · 0.8 mi
- Stop-N-Go IncUnderground Storage Tanks · 0.8 mi
- Tonkawa Public SchoolsUnderground Storage Tanks · 0.9 mi
- Jiffy Trip #327Underground Storage Tanks · 0.9 mi
- Kerr McgeeUnderground Storage Tanks · 0.9 mi
- Northern Oklahoma CollegeUnderground Storage Tanks · 1.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Tonkawa'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 Tonkawa.
Total Sites
115
within ~10 miles of Tonkawa
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Tonkawa
Severity Distribution
within ~10 miles of Tonkawa
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Tonkawa, two things run higher than the national average within ~10 miles of Tonkawa — Toxics Release Inventory (8 sites) and Underground Storage Tanks (78 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Tonkawa
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 Tonkawa average
Your land is one point inside Tonkawa
Everything above resolves to Tonkawa as a whole — one PHZM band and one 28°F frost record, read across 3K 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 Tonkawa Average
Tonkawa Average
- ●USDA Zones 7a, averaged across Tonkawa
- ●One soil character for all of Tonkawa
- ●Frost dates read at Tonkawa's scale: Mar 27 to Nov 10
YOUR Parcel
- ✓Your exact zone, not Tonkawa's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Tonkawa
Pull a site-specific report for your exact address in Tonkawa, Oklahoma — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Tonkawa averages can't show:
We read public map data around Tonkawa — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Tonkawa average
How we know this about Tonkawa
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 Tonkawa’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 Tonkawa
When does frost risk typically end in Tonkawa?
The last hard freeze (28°F) in Tonkawa typically lands around Mar 27, 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 17.
When is the first frost in Tonkawa?
The first hard freeze (28°F) in Tonkawa typically arrives around Nov 10, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 27, so the watching starts about Oct 11 — about 228 days after the spring freeze cleared.
How long is the growing season in Tonkawa?
Measured between 28°F hard freezes, Tonkawa sees about 228 frost-free days — roughly Mar 27 through Nov 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 17 to Oct 27, about 193 days.
Is the soil safe to grow vegetables in Tonkawa?
The federal record around Tonkawa is a meaningful one — 115 documented sites, mostly Underground Storage Tanks entries (78), the nearest Toxics Release Inventory record about 0.4 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.
How do I protect my plants from frost in Tonkawa?
From about Oct 11 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 Nov 10 (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 Nov 10. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Tonkawa's scale — its 7a band and its 228-day season. Your yard writes its own version of Tonkawa'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 Tonkawa’s own scale
6 of the readings below were taken at Tonkawa's own scale — its own ~228-day season between 28°F freezes, the 2,642 acres it covers and 115 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Tonkawa's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Tonkawa's own 28°F hard-freeze dates, about Mar 27 and Nov 10 and the ~228-day span between themNOAA 1991–2020 Climate Normals
- 115 documented contamination sites on the federal record near Tonkawa, the closest Toxics Release Inventory record about 0.4 miles out from the town centreFederal environmental registers
- Tonkawa's boundary and the 2,642 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~228-day seasonGrowable Ground crop-matching engine
- The ecoregion at Tonkawa's own centroid, the Central Great PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Tonkawa's 2,642 acres read through its county's SSURGO summaryfrom Kay County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Kay County
- The growing challenges every Oklahoma grower plans around — written at state scale, so they stay on the state guidefrom Oklahoma
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Kay County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Tonkawa's 2,642 acreswhy one lot differs from the next →
- Which side of Tonkawa you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,642 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Toxics Release Inventory record about 0.4 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 Tonkawa-wide figureread your own land →
More in Oklahoma
Wider growing context
What grows across OklahomaTonkawa sits outside our named growing regions, so Oklahoma as a whole is its closest context here.
Nearby growing guides