Dewey County, in Oklahoma, sits in USDA hardiness zone 7a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Expect pecan, tomato, okra, and redbud to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Dewey County holds more than one microclimate.
Soils and elevations shift across Dewey County, so your frost dates and drainage aren't the county average. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Quick Facts
USDA Zones
7a
Last Hard Freeze (28°F)
Mar 1
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Nov 26
County normal — light frosts arrive a few weeks earlier
County Area
640K acres
Hardiness Zone Range
Zone maps are averages across Dewey County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in Dewey County
Across Dewey County, the ground is predominantly Inceptisols, where Quinlan, Hardeman, and St. Paul are the most extensive named soil series. The soil is generally well drained with a loam surface. Topsoil pH runs about 7.2–7.9, slightly alkaline. Rainfall drains through hydrologic group A soils.
Soil order
Inceptisols
Drainage
Well drained
Prime farmland
38%
Hydric soils
1%
Soil still varies lot by lot — soil types explained.
What Grows in Dewey County
Plants matched to Dewey County's USDA zones 7a — each links to its full growing profile.
Is it too late to plant in Dewey County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 1 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 26 — long-season crops need about 90 days of runway, quick greens only 30. With almost year-round growing weather, timing is about heat and rainfall more than frost — some bench is always in play.
Growing Challenges in Oklahoma
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 Dewey County — and how to grow with it.
We checked the federal record across Dewey County — 110 documented sites across 6 of the 9 source types we track.
The most significant on record: 1 Toxics Release Inventory facility. Active industrial facilities reporting chemical releases to air, water, and land.
The federal record across Dewey County is a modest one — a typical footprint for a growing area. Nothing here calls for alarm; it's worth knowing which recorded sites sit closest to where you grow, and each one on the map carries its type and location. If one turns out to be a near neighbor, a one-time soil test settles the question.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Total Sites
110
across Dewey County
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
across Dewey County
Severity Distribution
across Dewey County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Dewey County, Nitrate runs higher than the national average — 34 sites nearby. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Dewey County
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Your Specific Parcel Matters
Dewey County Average
- ●USDA Zones 7a
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Dewey County
Pull a site-specific report for your exact address in Dewey County, Oklahoma — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Key Growing Facts for Dewey County, Oklahoma
- USDA Hardiness Zones: 7a (USDA PHZM 2023)
- Last Hard Freeze (28°F): Mar 1 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Nov 26 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~270 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 640K acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. County boundaries: US Census TIGER/Line 2025.
Frost dates here are the Dewey County average. Low spots and tree cover move them by days on any one yard — see your exact frost windows.
Frequently Asked Questions
What hardiness zone is Dewey County, Oklahoma?
Dewey County sits in USDA hardiness zone 7a, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
Is it too late to plant in Dewey County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 1 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 26 — long-season crops need about 90 days of runway, quick greens only 30. With almost year-round growing weather, timing is about heat and rainfall more than frost — some bench is always in play.
When does frost risk typically end in Dewey County?
The last hard freeze (28°F) in Dewey County typically lands around Mar 1, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.
How long is the growing season in Dewey County?
Measured between 28°F hard freezes, Dewey County sees about 270 frost-free days — roughly Mar 1 through Nov 26, per 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.
What vegetables grow in Dewey County?
Dewey County's zone 7a supports 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.
Which hardiness zone is Dewey County, really?
Officially, Dewey County sits in USDA zone 7a (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 1,112 plants against what's actually there.
Is the soil safe to grow vegetables in Dewey County?
The federal record around Dewey County shows 110 documented sites — 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.
Just moved to Dewey County — what should I know before planting?
Start with three facts. Dewey County sits in USDA zone 7a, which sets what survives winter; the last 28°F hard freeze typically clears around Mar 1, with about 270 frost-free days to work with (NOAA 1991–2020 climate normals); and 110 documented sites sit on the federal record — a typical footprint for a growing area, worth a look on the contamination map before food beds. From there, matching plants to your actual soil and sun is the fun part.
Everything on this page is a Dewey County average. Your yard writes its own version — 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.