Pinal County, in Arizona, sits in USDA hardiness zone 9b — a zone band wide enough that plant choice, not possibility, is the interesting question.
A short list that earns its place here — okra, meyer lemon, california poppy, and artichoke — with any one site's soil, sun, and drainage making the final cut.
Pinal County lies within the Sonoran Desert — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Pinal County holds more than one microclimate.
Soils and elevations shift across Pinal 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 Pinal County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Pinal County — the short answer
Pinal County, Arizona: USDA zone 9b, about 327 days between hard freezes, across 3.4M acres.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 23
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Dec 16
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~327
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 3.4M 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 9b is Pinal County's average, not your lot's — a low corner or a tree line moves it. Against Pinal County's 327-day season, see what your own ground reads.
Heat and winter chill in Pinal County
Across a year, Pinal County accumulates about 7,702 growing degree days above 50°F, about 2,943 more than the middle Arizona county — ahead of 11 of Arizona’s 15 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 608 hours below 45°F, 871 fewer than the Arizona middle of 1,479. 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 Pinal County
Across Pinal County, the ground is predominantly Aridisols, where Denure, Mohall, and Casa Grande are the most extensive named soil series. The soil is generally well drained with a sandy loam surface. Topsoil pH runs about 7.2–8.2, slightly alkaline. Rainfall drains through hydrologic group C soils.
Soil order
Aridisols
Drainage
Well drained
Hydric soils
0%
Soil still varies lot by lot — soil types explained.
How the ground varies across Pinal County
The USDA soil survey maps 75% of Pinal County as well drained — but another 20% drains differently: 17% somewhat excessively drained, 2% excessively drained.
Denure is the most extensive named soil at 10% of mapped acres, then Mohall (6%) and Casa Grande (5%).
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 Pinal County
Each reading below is measured for Pinal 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 Pinal County are well drained, in hydrologic group C — 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 Pinal County runs about pH 7.2–8.2, on the alkaline side.
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
Season length
MeasuredPinal County runs about 327 days between hard freezes — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredPinal County sits in USDA hardiness zone 9b.
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 Pinal County is in
Pinal County spans 3 EPA Level III ecoregions — Sonoran Basin and Range (80%), Madrean Archipelago (15%) and Arizona/New Mexico Mountains (5%). 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 Pinal County
We scored all 1,086 plants against Pinal County's own USDA zone 9b and its own 327-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 Arizona profile.
Is it too late to plant in Pinal County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Jan 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jan 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 16 — 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.
Documented around Pinal County
Survey cells within 31 miles of Pinal County checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 337 miles off. What to watch for.
- monarch butterfly8 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Pinal County
USGS estimates 270,947 lb of Glyphosate on Pinal County farmland in 2019, its largest by weight, ahead of Metolachlor-s (26,261 lb) and Metolachlor & Metolachlor-s (26,261 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 Pinal County — and how to grow with it.
We checked the federal record across Pinal County — 2,102 documented sites across 7 of the 9 source types we track.
The most significant on record: 11 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Pinal County 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.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Pinal County
Closest first, across Pinal County. Listing isn't leaking, and distance isn't exposure.
- YOLANDA'S CHUCKWAGONUnderground Storage Tanks · 3.3 mi
- COOLIDGE AIRPORTUnderground Storage Tanks · 3.3 mi
- D-05-10 28CCANitrate · 3.4 mi
- OASIS FELLOWSHIPUnderground Storage Tanks · 3.6 mi
- CITY OF COOLIDGE - MUNICIPAL AIRPORTUnderground Storage Tanks · 3.7 mi
- Unnamed ProspectMining · 4.0 mi
- D-05-10 26CDCNitrate · 4.8 mi
- AT&T - FLORENCE AZ3180Underground Storage Tanks · 5.3 mi
- AT&TUnderground Storage Tanks · 5.3 mi
- D-05-07 23DDANitrate · 5.4 mi
- D-06-09 07CB UNSURVNitrate · 5.5 mi
- D-06-09 07BBC1Nitrate · 5.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Pinal 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 Pinal County.
Total Sites
2,102
across Pinal County
Risk Level
High
Highest-severity
11 Superfund sites (none NPL-listed)
Sources Checked
across Pinal County
Severity Distribution
across Pinal County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Pinal County, two things run higher than the national average across Pinal County — Mining (580 sites) and Nitrate (802 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Pinal 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 Pinal County average
Your land is one point inside Pinal County
Everything above resolves to Pinal County as a whole — one PHZM band and one county frost record, read across 3.4M 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 Pinal County Average
Pinal County Average
- ●USDA Zones 9b, averaged across Pinal County
- ●One soil character for all of Pinal County
- ●Frost dates read at Pinal County's scale: Jan 23 to Dec 16
YOUR Parcel
- ✓Your exact zone, not Pinal County's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Pinal County
Pull a site-specific report for your exact address in Pinal County, Arizona — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Pinal County averages can't show:
We read public map data around Pinal County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Pinal County average
How we know this about Pinal 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 Pinal County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Pinal County
When does frost risk typically end in Pinal County?
The last hard freeze (28°F) in Pinal County typically lands around Jan 23, 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 Feb 13.
How long is the growing season in Pinal County?
Measured between 28°F hard freezes, Pinal County sees about 327 frost-free days — roughly Jan 23 through Dec 16, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 13 to Dec 2, about 292 days.
Is the soil safe to grow vegetables in Pinal County?
The federal record around Pinal County runs heavier than most — 2,102 documented sites, mostly Nitrate entries (802), the nearest Underground Storage Tanks record about 3.3 miles out — 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.
Everything above is measured at Pinal County's scale — its 9b band and its 327-day season. Your yard writes its own version of Pinal 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 Arizona's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Pinal County’s own scale
9 of the readings below were taken at Pinal County's own scale — its own ~327-day span between 28°F freezes, the 3 most extensive soil series mapped here and 2,102 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Pinal County's own USDA hardiness band, zones 9bUSDA PHZM 2023
- Pinal County's own 28°F hard-freeze dates and its ~327-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Pinal CountyUSDA NRCS SSURGO
- 2,102 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 3.3 miles outFederal environmental registers
- Pinal County's boundary and the 3,434,674 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~327-day seasonGrowable Ground crop-matching engine
- The 3 ecoregions Pinal County spans, Sonoran Basin and Range the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Pinal County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Pinal County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Arizona grower plans around — written at state scale, so they stay on the state guidefrom Arizona
What this page can’t tell you
- How the season shifts across Pinal County — the ~327 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 Pinal County's 3,434,674 acreswhy one lot differs from the next →
- Which of those 2,102 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 Pinal Countyread your own land →