Oklahoma spans USDA hardiness zones 6b-8b, with a growing season of about 237 frost-free days — long enough to run two plantings of many vegetables and still ripen the heat-lovers.
Those zone numbers rest on 15-56 inches of annual rainfall, a median of roughly 4,695 growing-degree days (base 50°F), and about 1,955 winter chill hours for tree fruit — the measurements that do the deciding. Soils here lean toward red clay, sandy loam, prairie loam, and alluvial, and each drains differently — the single trait that most often decides whether a crop takes hold. Between High Plains, The Ozarks, and Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country), the growing rules shift enough that zone and frost advice only turns precise once you pick your region. Growers here do well with pecan, tomato, okra, and redbud — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Grounded inUSDA PHZM•NOAA Climate Normals•USDA NRCS SSURGO•GDD (PRISM 1991-2020 normals)•Chill hours (PRISM 1991-2020 normals)•USDA hardiness sub-region map•EPA FRS•USDA PLANTS•Growable Ground suitability scoring
Oklahoma spans zones 6b-8b, but your yard sits in exactly one — and slope, tree cover, and low spots nudge it further. 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 Oklahoma — soil, climate, flood, and parcel records. How we handle your address.
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Distinct growing regions within Oklahoma — each has its own zones, soils, and signature crops.
Oklahoma: USDA zones 6b-8b, 197–267 frost-free days depending on the county, 77 counties.
The middle half of this state’s counties. Tender transplants usually wait 2–3 weeks past the last hard freeze. The shortest-season figure is Oklahoma's own county record — Cimarron County's measured 28°F normal, not a modeled floor.
Oklahoma does not have one growing season. Across the 829 of its 833 towns that carry their own 30-year record, the shortest measured season is Kenton's at 195 days and the longest is Grant's at 271 — a 76-day spread inside one state.
Neither end is a lone reading — another 14 towns measure within 10 days of Kenton and 18 sit within 10 days of Grant. These are real pockets, so the number to plant against is your own town's, not the state average.
NOAA Regional Climate Centers ACIS (1991–2020), 30-year daily minimum record
Zone 6b-8b is Oklahoma's average, not your lot's — a low corner or a tree line moves it. Against Oklahoma's 237-day season, see what your own ground reads.
One answer for Oklahoma averages 77 counties whose growing seasons are 70 days apart — from 197 frost-free days in Cimarron County to 267 in Choctaw County. That is the same state, measured the same way, in the same years. Which end of it your county sits nearer decides what finishes before the first hard freeze.
The middle half of 77 counties runs 229–244 days, with a median of 237 days — a 70-day span end to end.
Measured across 77 counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. A county with no record of its own is absent from the range rather than counted as zero — nothing here is interpolated to the state. Your own site sits somewhere inside this range; a parcel report resolves where.
The middle half of Oklahoma runs 229–244 frost-free days, and 35 of its 77 counties sit outside that — 17 on the short side, 18 on the long. A statewide planting date describes the middle well and the ends poorly, which is worth knowing before you follow one.
Under 229 frost-free days
17 counties
3 of 17 shown
The end of the state that sets the planting calendar — start seed indoors here and the season stretches to meet the crop.
229–244 frost-free days
42 counties
0 of 42 shown
The middle half of the state, and the part a single statewide date describes well.
Over 244 frost-free days
18 counties
3 of 18 shown
Long enough for a second succession of a quick crop after the first comes out.
Each county is placed by its own 28°F frost-free normal (NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze), the same figure its own guide page publishes. Elevation, slope and cold-air drainage move a yard within its county as well — which is the part only your address resolves.
The soil types that dominate Oklahoma — how each drains decides more about crop success than almost anything else. Tap any soil to learn what it is and how to work with it. Each photo is a representative profile of that soil type; the named series is where it was documented, which is often another state.
Drainage
Slow. Red clay seals under pounding rain and sheds water across the surface, then holds tight to what soaks in.
What thrives
Okra, southern peas, sweet potatoes, and muscadines are traditional red-clay performers, and many fruit trees root deep into it once through the first year. Azaleas and blueberries appreciate its typical acidity.
Drainage
Fast. The sand fraction opens the soil up, so water moves through the root zone quickly and the surface rarely stays soggy. The trade is that nutrients ride out with the water.
What thrives
Root crops love it — carrots, potatoes, radishes, and onions size up cleanly in ground they can push through. Melons, sweet potatoes, asparagus, and most herbs appreciate the warmth and the drainage.
Drainage
Good. The crumb structure that prairie roots built lets water in and holds it like a sponge, releasing it steadily through the season.
What thrives
This is some of the most productive crop ground on Earth — corn, beans, squash, brassicas, and nearly any vegetable you plant. Prairie natives like coneflower and big bluestem are, unsurprisingly, right at home.
Drainage
Usually good: rivers sort their loads, and most alluvial soils have enough sand and silt to move water while holding plenty for roots. Low-lying pockets can run wet.
What thrives
Nearly everything — vegetables, orchards, vines, and berries all prosper on alluvium. Its depth lets roots go as far down as they care to.
Soil data: USDA NRCS SSURGO · Soil types explained
Plants well-suited to Oklahoma's climate, soils, and growing season — each links to its full growing profile.
Rarely: the season closes in stages, not all at once, and each stage has its crops. Across Oklahoma, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Mar 20, with the middle half of counties between Mar 15 and Mar 26 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Nov 9 and Nov 14 — 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.
The plants Oklahoma put its name on — cultural emblems, not growing recommendations.
Oklahoma rose
Rosa
Designated 2004.
Cercis canadensis
Designated 1971. In our plant library — see its full growing profile.
Designated 2007. In our plant library — see its full growing profile.
Plants the USDA PLANTS Database documents as native and present in Oklahoma — a real per-state range, not just a zone match. Ordered by how closely each plant’s published hardiness range matches Oklahoma’s zones 6b-8b, so this is a shortlist by climate fit, not a ranking of which plants matter most here. Presence is statewide, so a plant may still be uncommon in your specific county; your state’s Cooperative Extension or a native-plant society is the local authority.
US-native plants whose hardiness range overlaps Oklahoma’s USDA zones 6b-8b but which USDA PLANTS doesn’t map to a single state range here. Zone overlap is a starting filter, not a range map.
What an experienced grower plans around here — each one has a move.
Extreme weather variability (tornadoes, ice storms, drought)
Flexible beats fortified here: row covers staged, storm-tough perennials, and quick-replant annual beds.
Red clay soils drain poorly in central OK
A raised bed ends the standing-water fight in a weekend, and fall compost keeps opening the clay below.
Low western rainfall requires irrigation
Western plots run on drip and mulch — plan the water before the planting and the dry years lose their teeth.
For cultivar selection, pest pressure, and planting-time guidance specific to Oklahoma, the Oklahoma State University Extension is the authoritative local source.
Safe to Grow Here?What the federal record shows across Oklahoma — and how to grow with it.
We checked the federal record across Oklahoma — 24,720 documented sites across 8 of the 9 source types we track.
The most significant on record: 151 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Oklahoma carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Severity Distribution
across Oklahoma
Highest-Severity Sites
Know Before You Grow
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Everything above resolves to Oklahoma as a whole — a state whose own counties record seasons 70 days apart, and hardiness across zones 6b-8b. Your parcel sits at one point in that range, not in the middle of it. 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 state 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 statewide average.
State averages sketch the shape. Your soil, sun exposure, drainage, and microclimate decide what actually takes. Pull a site-specific report for your exact parcel.
Enter your address. We read your soil, sun, drainage, and frost dates, then score 1,086 plants against the real conditions on your land.
Three things about your lot that Oklahoma averages can't show:
We read public map data around Oklahoma — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Oklahoma average
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read per county and aggregated to the state band; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each county’s own record; rainfall from NOAA Climate Normals; soils from USDA NRCS SSURGO; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above. Where a county carries no record of its own, it is absent from the figure rather than filled in.
Oklahoma spans USDA hardiness zones 6b-8b — which is to say winter's coldest night runs from about −5°F to 20°F depending where in Oklahoma you are, averaged over 1991–2020 (USDA PHZM 2023).
Rarely: the season closes in stages, not all at once, and each stage has its crops. Across Oklahoma, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Mar 20, with the middle half of counties between Mar 15 and Mar 26 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Nov 9 and Nov 14 — 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.
Across Oklahoma, the middle half of counties see their last hard freeze (28°F) between about Mar 15 and Mar 26, with a county median near Mar 20 (NOAA 1991–2020 climate normals). 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 10.
Measured between 28°F hard freezes, growing seasons across Oklahoma's counties mostly run about 229 to 244 days, with a county median near 237 (NOAA 1991–2020 climate normals). Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
Oklahoma's zones 6b-8b support a wide range — strong performers include Pecan, Tomato, Okra, Redbud, and Blackberry. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Officially, Oklahoma spans USDA zones 6b-8b (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,086 plants against what's actually there.
The federal record across Oklahoma runs heavier than most — 24,720 documented sites, mostly Underground Storage Tanks entries (13,488) — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Start with three facts. Oklahoma spans USDA zones 6b-8b, which sets what survives winter; last hard freezes range from about Mar 15 to Mar 26 across its counties (NOAA 1991–2020 climate normals); and 24,720 documented sites sit on the federal record here, so a soil test before food beds is the smart first step. From there, matching plants to your actual soil and sun is the fun part.
Everything above is measured at Oklahoma's scale — its 6b-8b band and its 237-day season. Your yard writes its own version of Oklahoma's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
6 of the readings below were taken at Oklahoma's own scale — the full zone 6b-8b span inside its borders, the 4 soil types that dominate its ground and 24,720 documented sites on its federal record; anything it cannot resolve at this scale is named below.
Measured here
What this page can’t tell you
Explore growing conditions by county — each has its own zone range and land area.
Explore growing conditions by city or town in Oklahoma.
Oklahoma shares its dominant growing region with these states — a useful comparison if you're weighing where a crop will behave the same way.
