The High Plains spans USDA hardiness zones 4b-8b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
A semi-arid shortgrass tableland of deep soils and big sky, where wind, low rainfall, and irrigation shape dryland wheat, sorghum, and resilient gardens. Crops well matched to these conditions include tomato, sunflower, sweet corn, and green chile — though what thrives on any one site still turns on its specific soil, sun, and drainage.
The High Plains spans Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas and Wyoming. Its footprint follows the EPA Level III ecoregion boundary; the counties linked below are representative of the region, not an exhaustive list.
Your yard isn't all of the High Plains.
The High Plains spans USDA zones 4b-8b, 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 High Plains — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
The High Plains — the short answer
The High Plains: USDA zones 4b-8b, 134–270 frost-free days depending where in it you stand, across 7 states.
- USDA zones
- 4b-8b
- USDA PHZM 2023, aggregated over the footprint
- Shortest season here
- 134 days
- NOAA Regional Climate Centers ACIS, 1991-2020 — Sioux County
- Counties
- 86
- US Census TIGER/Line 2025
- Region type
- EPA ecoregion
- 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. The season figure is this region's own record, measured across its 86 member counties, not a state or national average.
Hardiness Zone Range
The High Plains is not one growing season
One answer for the High Plains averages 86 counties whose growing seasons are 136 days apart — from 134 frost-free days in Sioux County to 270 in Upton County. That is the same region, measured the same way, in the same years. Which end of it your land sits nearer decides what finishes before the first hard freeze.
The middle half of 86 counties runs 178–223 days, with a median of 197 days — a 136-day span end to end.
Measured across 86 member counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020. A member with no own record is absent from the range rather than counted as zero — nothing here is interpolated to the region. Your own site sits somewhere inside this range; a parcel report resolves where.
Where the line runs inside the High Plains
The middle half of the High Plains runs 178–223 frost-free days, and 42 of its 86 counties sit outside that — 21 on the short side, 21 on the long. A regional planting date describes the middle well and the ends poorly, which is worth knowing before you follow one.
Under 178 frost-free days
21 counties
- Sioux County · 134 days
- Goshen County · 151 days
- Laramie County · 154 days
3 of 21 shown
The end of the region that sets the planting calendar — start seed indoors here and the season stretches to meet the crop.
178–223 frost-free days
44 counties
0 of 44 shown
The middle half of the region, and the part a single regional season describes well.
Over 223 frost-free days
21 counties
- Upton County · 270 days
- Ector County · 263 days
- Crane County · 262 days
3 of 21 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), the same figure its own guide page publishes. Elevation, slope and cold-air drainage move a site within its county as well — which is the part only your address resolves.
What Grows in the High Plains
All 10 of the plants below that publish a season requirement clear even Sioux County’s 134 frost-free days — so on season alone, this grid works at both ends of the region. The 136-day spread still decides how far past this list you can push, and how early you can start.
Plants matched to the High Plains' USDA zones 4b-8b, 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 High Plains
Plants the USDA PLANTS Database documents as native and present in all 7 states this region crosses, kept only where the published hardiness range meets the High Plains’s USDA zones 4b-8b — 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 High Plains
The USDA soil survey maps this ground county by county. These are those records weighted by land area across 86 member counties — this region’s own profile, not a state figure.
The ground is predominantly Mollisols, at 50% of mapped acres, followed by Entisols (18%), Alfisols (15%) and Aridisols (11%). 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 Pullman, Amarillo, and Valent.
87% of those acres are well drained, and another 8% excessively drained, 2% somewhat excessively drained. Topsoil pH runs 6.5–8.2 between the lowest and the highest county on record. 12% of the footprint is classed prime farmland.
Soil order
Mollisols
Drainage
Well drained
Topsoil pH
6.5–8.2
Hydric soils
1%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. Hale County holds the most wetland ground here, at 4% — soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the High Plains
The soil survey reads this ground county by county, and the readings above are those records summed across the High Plains. Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records87% of the mapped acres across the High Plains are well drained — ground that drains quickly. That is area-weighted across all 86 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 High Plains runs pH 6.5–8.2 — alkaline in 55 of its 86 counties.
Many vegetables cope, but acid-lovers like blueberries struggle, and iron and manganese lock up above about pH 7.5 — leaves yellow between the veins even in rich soil.
Elemental sulfur and generous organic matter lower pH slowly for the beds that need it; test first so you add only what the soil actually calls for.
USDA NRCS SSURGO
Safe to Grow Here?
What the federal record shows across the High Plains — and how to grow with it.
Across the High Plains' 86 counties the federal record holds 24,830 documented sites, mostly Underground Storage Tanks (11,619), Nitrate (6,778) and Brownfields (4,491). The heaviest single county is Denver County, with 2,786.
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 High Plains to see which records sit where you actually grow.
Sources Checked
Summed across the 86 counties in the High Plains
A note from Gnorman
What an experienced grower watches for around here
In and around the High Plains, two things run higher than the national average across the 86 counties in the High Plains — CAFO (732 sites) and Nitrate (6,778 sites). That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
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 High Plains
Everything above resolves to the High Plains as a whole — a footprint whose own counties record seasons 136 days apart, and hardiness across zones 4b-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 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 High Plains Average
High Plains Average
- ●USDA Zones 4b-8b, averaged across High Plains
- ●One soil character for all of High Plains
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not High Plains' 4b-8b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the High Plains
Pull a site-specific report for your exact address in the High Plains — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that High Plains averages can't show:
We read public map data around The High Plains — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the High Plains average
How we know this about the High Plains
The boundary: an EPA Level III ecoregion (an area sharing climate, soils, and vegetation). 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 High Plains
What hardiness zone is the High Plains?
The High Plains spans USDA hardiness zones 4b-8b, 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 High Plains?
Measured between 28°F hard freezes, the High Plains' counties mostly run 178 to 223 frost-free days, median 197 (NOAA Regional Climate Centers ACIS, 1991–2020, over 86 member counties). That 45-day spread is the honest read — no single season describes 86 counties, and each county guide below carries its own.
When does frost risk end in the High Plains?
Across the High Plains, the middle half of member counties see their last 28°F hard freeze between Mar 30 and Apr 23 (median Apr 13), and their first fall freeze between Oct 18 and Nov 8. Those are hard freezes, not the last light frost: tender transplants wait for about May 4, and elevation decides which end of a 24-day spread you garden in.
What grows well in the High Plains?
The High Plains' conditions suit plants such as Tomato, Sunflower, Sweet Corn, Green Chile, Okra, Potato. 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 High Plains defined?
The High Plains' footprint follows an EPA Level III ecoregion — a boundary drawn where climate, soils, and vegetation actually change rather than where a state line falls. It covers 86 counties, and the counties linked on this page are representative of the region, not an exhaustive list.
Which states does the High Plains cover?
The High Plains spans Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, and Wyoming. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
The Ozarks, Piney Woods, Texas High Plains / Panhandle, Gulf Coast, Nebraska Sandhills, and Blackland Prairie share at least one state with the High Plains. 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 High Plains’s own scale
6 of the readings below were taken at the High Plains' own scale — the zone 4b-8b band across its footprint, a median 197-day season across its 86 counties and 24,830 documented federal contamination records across its 86 counties, 2,786 of them in Denver County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 4b-8b aggregated across all 86 counties in the footprintUSDA PHZM 2023
- The boundary itself — the EPA Level III ecoregion its 86 counties sit inside, drawn where climate and soils changeEPA Level III Ecoregions
- 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 86 counties run 178 to 223 frost-free days, median 197NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 24,830 documented federal contamination records across its 86 counties, 2,786 of them in Denver County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 50% Mollisols, topsoil pH 6.5–8.2, area-weighted across its 86 mapped countiesUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — all 7 member states' curated sets, merged and filtered to zones 4b-8bfrom Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas and Wyoming
What this page can’t tell you
- Which end of the 45-day range your ground sits at — 178 days at one extreme, 223 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 High Plains
State growing guides
Representative counties
Other growing regions across Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, and Wyoming
A rugged Interior Highlands of cherty, rocky soils, oak-hickory forest, and clear streams — brambles, peaches, and tough hill gardens.
The sandy, acidic pine-and-hardwood forest belt of East Texas and western Louisiana — the humid South Central Plains, where a long frost-free season of roughly nine months favors heat- and acid-tolerant Southern gardens.
The southern, warmer anchor of the High Plains — the Llano Estacado tableland west of the Caprock Escarpment, where a longer season (frost-free days run near 227 across the Texas counties, well above the multi-state High Plains average) and deep-well Ogallala irrigation define the growing reality. This is the largest contiguous cotton patch in the world around Lubbock (Texas Co-op Power), and, west of the Caprock, the Texas High Plains AVA (TTB, 27 CFR 9.144) that grows roughly 80% of the state's wine grapes. High, flat, and semi-arid: what grows here is what deep-well water and a zone 7a-8a season can coax from it, a distinctly Texan story rather than the dryland wheat and sorghum of the northern High Plains.
The humid, near-frost-free coastal rim of the Gulf of Mexico — long seasons, sandy and alluvial soils, heat, and hurricanes shaping what thrives. (Representative coastal counties, not exhaustive.)
The largest sand-dune field in the Western Hemisphere, stabilized under prairie grass — grazing country where gardening means windbreaks and sandy-soil care.
Here the soil, not the zone, defines the garden. The Blackland Prairie is a narrow black-clay belt tracing the I-35 corridor from Sherman through Dallas, Waco, and Temple down to Austin — built on vertisol "black gumbo" that swells sticky when wet, then cracks open as it dries. That shrink-swell clay is alkaline and slow-draining, so where the sandy acid soils of the Piney Woods to the east or the thin limestone of the Hill Country to the west let many gardeners plant straight in the ground, growers here reach for raised beds, gypsum, and heavy organic amendment first. The season runs long — commonly 264 to 300 frost-free days across zones 8a to 9a — but it's the black clay, not the calendar, your beds have to answer to.