The Arkansas River Valley spans USDA hardiness zones 7b-8a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
The Arkansas River Valley — one of Arkansas's six natural divisions, threading the Arkansas River between the Ozark and Ouachita Mountains — spans USDA zones 7b to 8a across its eight member counties, with frost-free seasons of roughly 243 to 254 days. Expect tomato, sweet potato, peach, and muscadine grape to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
The Arkansas River Valley spans Arkansas.
Your yard isn't all of the Arkansas River Valley.
The Arkansas River Valley spans USDA zones 7b-8a, but your parcel 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 Arkansas River Valley — soil, climate, flood, and parcel records. How we handle your address.
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The Arkansas River Valley — the short answer
The Arkansas River Valley: USDA zones 7b-8a, 243–254 frost-free days, in Arkansas.
- USDA zones
- 7b-8a
- USDA PHZM 2023, aggregated over the footprint
- Frost-free season
- 243–254 days
- NOAA Regional Climate Centers ACIS, 1991-2020
- Counties
- 8
- US Census TIGER/Line 2025
- Region type
- County cluster
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. Where a region publishes no measured season, no season figure is shown.
Hardiness Zone Range
What Grows in the Arkansas River Valley
Plants matched to the Arkansas River Valley's USDA zones 7b-8a, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of the Arkansas River Valley
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets the Arkansas River Valley’s USDA zones 7b-8a — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground across the Arkansas River Valley
The USDA soil survey maps this ground county by county. These are those records weighted by land area across eight member counties — this region’s own profile, not a state figure.
The ground is predominantly Ultisols, at 86% of mapped acres, followed by Inceptisols (4%), Alfisols (4%) and Entisols (3%). Six soil orders appear somewhere inside the footprint, which is the honest reason a regional soil answer only goes so far. The most extensive named soils are Mountainburg, Enders, and Leadvale.
72% of those acres are well drained, and another 16% moderately well drained, 4% somewhat poorly drained. Topsoil pH runs 5.0–5.6 between the lowest and the highest county on record. 26% of the footprint is classed prime farmland.
Soil order
Ultisols
Drainage
Well drained
Topsoil pH
5.0–5.6
Hydric soils
4%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. Yell County holds the most wetland ground here, at 7% — soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Arkansas River Valley
The soil survey reads this ground county by county, and the readings above are those records summed across the Arkansas River Valley. Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records72% of the mapped acres across the Arkansas River Valley are well drained — ground that drains quickly. That is area-weighted across all eight of its mapped counties.
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
From county recordsTopsoil across the Arkansas River Valley runs pH 5.0–5.6 — acidic in all eight of them.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Safe to Grow Here?
What the federal record shows across the Arkansas River Valley — and how to grow with it.
Across the Arkansas River Valley's 8 counties the federal record holds 2,578 documented sites, mostly Underground Storage Tanks (1,219), Nitrate (870) and Brownfields (305). The heaviest single county is Sebastian County, with 788.
That is a regional count, not a reading of any one lot — proximity to a documented site is information, not a diagnosis. Open the map outlined to the Arkansas River Valley to see which records sit where you actually grow.
Sources Checked
Summed across the 8 counties in the Arkansas River Valley
A note from Gnorman
What an experienced grower watches for around here
In and around the Arkansas River Valley, Nitrate runs higher than the national average — 870 sites across the 8 counties in the Arkansas River Valley. 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.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside the Arkansas River Valley
Everything above resolves to the Arkansas River Valley as a whole — a footprint spanning USDA zones 7b-8a. Your parcel sits in exactly one of them. 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 region 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 regional average.
Your Lot vs the Arkansas River Valley Average
Arkansas River Valley Average
- ●USDA Zones 7b-8a, averaged across Arkansas River Valley
- ●One soil character for all of Arkansas River Valley
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Arkansas River Valley's 7b-8a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Arkansas River Valley
Pull a site-specific report for your exact address in the Arkansas River Valley — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Arkansas River Valley averages can't show:
We read public map data around The Arkansas River Valley — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Arkansas River Valley average
How we know this about the Arkansas River Valley
The boundary: a cluster of neighboring counties. Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the counties inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about the Arkansas River Valley
What hardiness zone is the Arkansas River Valley?
The Arkansas River Valley spans USDA hardiness zones 7b-8a, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's counties. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
How long is the growing season in the Arkansas River Valley?
Measured between 28°F hard freezes, the Arkansas River Valley's counties mostly run 245 to 252 frost-free days, median 248 (NOAA Regional Climate Centers ACIS, 1991–2020, over 8 member counties). That 7-day spread is the honest read — no single season describes 8 counties, and each county guide below carries its own.
When does frost risk end in the Arkansas River Valley?
Across the Arkansas River Valley, the middle half of member counties see their last 28°F hard freeze between Mar 13 and Mar 16 (median Mar 14), and their first fall freeze between Nov 15 and Nov 18. Those are hard freezes, not the last light frost: tender transplants wait for about Apr 4, and elevation decides which end of a 3-day spread you garden in.
What grows well in the Arkansas River Valley?
The Arkansas River Valley's conditions suit plants such as Tomato, Sweet Potato, Peach, Muscadine Grape, Blackberry. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is the Arkansas River Valley defined?
The Arkansas River Valley is defined here as a curated cluster of 8 neighboring counties that share a growing character. Growing regions have no official boundary, so this footprint is our published one — every county in it is named on this page.
Which states does the Arkansas River Valley cover?
The Arkansas River Valley spans Arkansas. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Mississippi Delta, The Ozarks, West Gulf Coastal Plain (South Arkansas), Ouachita Mountains, and Crowley's Ridge share at least one state with the Arkansas River Valley. Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at the Arkansas River Valley’s own scale
6 of the readings below were taken at the Arkansas River Valley's own scale — the zone 7b-8a band across its footprint, a median 248-day season across its 8 counties and 2,578 documented federal contamination records across its 8 counties, 788 of them in Sebastian County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 7b-8a aggregated across all 8 counties in the footprintUSDA PHZM 2023
- The boundary itself — the 8 counties this region is curated fromGrowable Ground subregion registry
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The 28°F season across the footprint — the middle half of its 8 counties run 245 to 252 frost-free days, median 248NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 2,578 documented federal contamination records across its 8 counties, 788 of them in Sebastian County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 86% Ultisols, topsoil pH 5.0–5.6, area-weighted across its 8 mapped countiesUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 7b-8afrom Arkansas
What this page can’t tell you
- Which end of the 7-day range your ground sits at — 245 days at one extreme, 252 at the other, decided mostly by elevationfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore the Arkansas River Valley
State growing guides
Counties in this region
Other growing regions across Arkansas
The flat, deep, dark alluvial bottomland of the lower Mississippi River — extraordinarily fertile cotton, soybean, rice, and sweet-potato ground.
A rugged Interior Highlands of cherty, rocky soils, oak-hickory forest, and clear streams — brambles, peaches, and tough hill gardens.
South Arkansas's pine Timberlands are the warmest, longest-season corner of the state — USDA zones 8a-8b with roughly 256-278 frost-free days (per county_data.json) — but the real signature is the ground: sandy, acidic, well-drained Coastal Plain soils under the pine belt, not the heavy dark alluvium of the Delta to the east or the rocky uplands to the north. That pairing — a long southern season on light, low-pH pine-flatwoods beds — pushes the playbook toward acid-tolerant and heat-loving Southern staples, raised quick-draining beds, and liming/organic-matter management that the Delta and mountain pages never need to cover. Around El Dorado, Camden, Magnolia, and Texarkana this is a distinct crop-and-soil story the statewide and tidal gulf-coast pages both miss.
Arkansas's Ouachita Mountains run in long east-west acidic rock ridges and cool hollows — an Interior Highlands division of thin cherty soil and steep slope aspect, unlike any flat ground in the state. The higher western counties hold zone 7b-8a and a shorter frost-free window (Montgomery ~232 days, Polk ~245) than the 8a bottomlands, so hill gardening here is a slope, aspect, and drainage story the state's 8a/254 median can't tell.
A loess ridge rising two hundred feet out of the Delta's flatness — the well-drained upland that carried Arkansas's historic orchards, running 7b-8a from Piggott to Helena through country that is otherwise alluvial bottomland; the differentiator is the ground itself: deep, drained loess where the Delta holds water.