Grady County, in Oklahoma, sits in USDA hardiness zone 7b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Among the crops suited to this profile: cabbage, prickly pear, california poppy, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Grady County holds more than one microclimate.
Soils and elevations shift across Grady 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 Grady County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Grady County — the short answer
Grady County, Oklahoma: USDA zone 7b, about 237 days between hard freezes, across 704K acres.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 20
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 12
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~237
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 704K 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 7b is Grady County's average, not your lot's — a low corner or a tree line moves it. Against Grady County's 237-day season, see what your own ground reads.
Heat and winter chill in Grady County
Across a year, Grady County accumulates about 4,863 growing degree days above 50°F, about 143 more than the middle Oklahoma county — ahead of 53 of Oklahoma’s 77 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.
Winter banks about 1,857 hours below 45°F, 62 fewer than the Oklahoma middle of 1,919. Chill is what tells a fruit tree its dormancy is over, and it is set by climate rather than by anything you can build.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Grady County
Across Grady County, the ground is predominantly Mollisols, where Stephenville, Grant, and Lucien are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 5.9–7.0, slightly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
46%
Hydric soils
0%
Soil still varies lot by lot — soil types explained.
How the ground varies across Grady County
The USDA soil survey maps 94% of Grady County as well drained — but another 4% drains differently: 2% somewhat poorly drained, 2% moderately well drained.
Stephenville is the most extensive named soil at 15% of mapped acres, then Grant (9%) and Lucien (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 Grady County
Each reading below is measured for Grady 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 Grady County are well drained, in hydrologic group B — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Grady County runs about pH 5.9–7.0, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredGrady County runs about 237 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
MeasuredGrady County sits in USDA hardiness zone 7b.
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 Grady County is in
Grady County spans 2 EPA Level III ecoregions — Central Great Plains (66%) and Cross Timbers (34%). 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 Grady County
We scored all 1,086 plants against Grady County's own USDA zone 7b and its own 237-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 Oklahoma profile.
Is it too late to plant in Grady County?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Feb 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 20 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 12 — 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.
Documented around Grady County
- monarch butterfly1 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Grady County
USGS estimates 64,553 lb of 2,4-d on Grady County farmland in 2019, its largest by weight, ahead of Triclopyr (28,171 lb) and Glyphosate (19,627 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 Grady County — and how to grow with it.
We checked the federal record across Grady County — 539 documented sites across 7 of the 9 source types we track.
The most significant on record: 2 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Grady County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Grady County
Closest first, across Grady County. Listing isn't leaking, and distance isn't exposure.
- MCNEFF DAIRY FARMCAFO · 1.6 mi
- Murphy Usa #7265Underground Storage Tanks · 1.7 mi
- ROB LOWE INCBrownfields · 1.8 mi
- 06N-07W-11 CBB 1Nitrate · 1.9 mi
- B & F QuickshopUnderground Storage Tanks · 2.1 mi
- M-CO PACKAGING, LTD.Toxics Release Inventory · 2.2 mi
- FORUM ENERGY TECHNOLOGIESToxics Release Inventory · 2.2 mi
- R & L Rental Tool Co., IncUnderground Storage Tanks · 2.2 mi
- Wal Mart Store #113Underground Storage Tanks · 2.3 mi
- Former OtascoUnderground Storage Tanks · 2.4 mi
- Usda Water Quality & WatersheUnderground Storage Tanks · 2.4 mi
- 07N-06W-32 AB 1Nitrate · 2.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Grady 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 Grady County.
Total Sites
539
across Grady County
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Severity Distribution
across Grady County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Grady County, two things run higher than the national average across Grady County — Nitrate (242 sites) and CAFO (6 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check your specific parcel in Grady 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 Grady County average
Your land is one point inside Grady County
Everything above resolves to Grady County as a whole — one PHZM band and one county frost record, read across 704K 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 Grady County Average
Grady County Average
- ●USDA Zones 7b, averaged across Grady County
- ●One soil character for all of Grady County
- ●Frost dates read at Grady County's scale: Mar 20 to Nov 12
YOUR Parcel
- ✓Your exact zone, not Grady County's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Grady County
Pull a site-specific report for your exact address in Grady County, Oklahoma — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Grady County averages can't show:
We read public map data around Grady County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Grady County average
How we know this about Grady 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 Grady County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Grady County
When does frost risk typically end in Grady County?
The last hard freeze (28°F) in Grady County typically lands around Mar 20, 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 10.
How long is the growing season in Grady County?
Measured between 28°F hard freezes, Grady County sees about 237 frost-free days — roughly Mar 20 through Nov 12, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 10 to Oct 29, about 202 days.
Is the soil safe to grow vegetables in Grady County?
The federal record around Grady County is a meaningful one — 539 documented sites, mostly Nitrate entries (242), the nearest CAFO record about 1.6 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.
Everything above is measured at Grady County's scale — its 7b band and its 237-day season. Your yard writes its own version of Grady 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 Oklahoma's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Grady County’s own scale
9 of the readings below were taken at Grady County's own scale — its own ~237-day span between 28°F freezes, the 3 most extensive soil series mapped here and 539 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Grady County's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Grady County's own 28°F hard-freeze dates and its ~237-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Grady CountyUSDA NRCS SSURGO
- 539 documented contamination sites inside the county boundary, distance-sorted from its center — the closest CAFO record about 1.6 miles outFederal environmental registers
- Grady County's boundary and the 704,345 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~237-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Grady County spans, Central Great Plains the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Grady County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Grady County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Oklahoma grower plans around — written at state scale, so they stay on the state guidefrom Oklahoma
What this page can’t tell you
- How the season shifts across Grady County — the ~237 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 Grady County's 704,345 acreswhy one lot differs from the next →
- Which of those 539 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 Grady Countyread your own land →