San Tan Valley, Arizona, sits in USDA hardiness zone 9b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Reliable performers under these conditions include okra, meyer lemon, california poppy, and artichoke; what your own ground favors still comes down to its soil, sun, and drainage.
Even in San Tan Valley, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single San Tan Valley lot. 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 San Tan Valley — soil, climate, flood, and parcel records. How we handle your address.
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San Tan Valley — the short answer
San Tan Valley, Arizona: USDA zone 9b, about 327 days between hard freezes, across 49K acres of town.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 23
- Pinal County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 16
- Pinal County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~327
- Pinal County normal — NOAA 1991–2020, nearest to this town
- Town area
- 49K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Pinal County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is San Tan Valley's average, not your lot's — a low corner or a tree line moves it. Against San Tan Valley's 327-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in San Tan Valley
Each reading below is measured for San Tan Valley itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSan Tan Valley runs about 327 days between hard freezes (read from Pinal County, the closest normal to San Tan Valley) — 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
MeasuredSan Tan Valley 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 San Tan Valley is in
San Tan Valley sits in the Sonoran Basin and Range — EPA Level III, inside the wider North American Deserts. That is read at San Tan Valley's own centroid rather than borrowed from Pinal County.
What Grows in San Tan Valley
Every plant below cleared San Tan Valley's own zone 9b and its 327-day season. Each card opens that plant's Arizona profile. How we score.
Is it too late to plant in San Tan Valley?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. 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. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
Documented around San Tan Valley
Survey cells within 31 miles of San Tan Valley checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 325 miles off. What to watch for.
What's on the federal record near San Tan Valley
Closest first, within ~10 miles of San Tan Valley. Listing isn't leaking, and distance isn't exposure.
- D-03-08 08BBBNitrate · 0.8 mi
- CIRCLE K #2705918Underground Storage Tanks · 1.1 mi
- WALGREENS #1076Brownfields · 1.2 mi
- QUIKTRIP #495Underground Storage Tanks · 1.3 mi
- FRYS FUEL CENTER #84Underground Storage Tanks · 1.3 mi
- CIRCLE K STORE #2741610Underground Storage Tanks · 2.1 mi
- HUGHES & GANZ CATTLE COUnderground Storage Tanks · 2.2 mi
- NEW MAGMA IRRIGATION & DRAINAGE DISTRICTUnderground Storage Tanks · 2.2 mi
- WALGREENS #9840Brownfields · 2.3 mi
- WALMART SUPERCENTER #3751Brownfields · 2.4 mi
- BANNER - IRONWOOD MEDICAL CENTERBrownfields · 2.5 mi
- J O COMBS MIDDLE SCHOOLUnderground Storage Tanks · 2.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from San Tan Valley'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 San Tan Valley.
Total Sites
174
within ~10 miles of San Tan Valley
Risk Level
Moderate
Highest-severity
12 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of San Tan Valley
Severity Distribution
within ~10 miles of San Tan Valley
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around San Tan Valley, two things run higher than the national average within ~10 miles of San Tan Valley — Mining (14 sites) and Toxics Release Inventory (12 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.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in San Tan Valley
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 San Tan Valley average
Your land is one point inside San Tan Valley
Everything above resolves to San Tan Valley as a whole — one PHZM band, read across 49K acres, with hard-freeze dates borrowed from Pinal County’s record because no 30-year normal resolves at this town’s own centroid. 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 town 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 local average.
Your Lot vs the San Tan Valley Average
San Tan Valley Average
- ●USDA Zones 9b, averaged across San Tan Valley
- ●One soil character for all of San Tan Valley
- ●Frost dates read at San Tan Valley's scale: Jan 23 to Dec 16
YOUR Parcel
- ✓Your exact zone, not San Tan Valley's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in San Tan Valley
Pull a site-specific report for your exact address in San Tan Valley, Arizona — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that San Tan Valley averages can't show:
We read public map data around San Tan Valley — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the San Tan Valley average
How we know this about San Tan Valley
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Pinal County’s record, because none resolves here; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about San Tan Valley
When does frost risk typically end in San Tan Valley?
The last hard freeze (28°F) in San Tan Valley 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.
When is the first frost in San Tan Valley?
The first hard freeze (28°F) in San Tan Valley typically arrives around Dec 16, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 2, so the watching starts about Nov 16 — about 327 days after the spring freeze cleared.
How long is the growing season in San Tan Valley?
Measured between 28°F hard freezes, San Tan Valley 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 San Tan Valley?
The federal record around San Tan Valley shows 174 documented sites, mostly Underground Storage Tanks entries (55), the nearest Nitrate record about 0.8 miles out — 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.
How do I protect my plants from frost in San Tan Valley?
From about Nov 16 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Dec 16 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Dec 16. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at San Tan Valley's scale — its 9b band and its 327-day season. Your yard writes its own version of San Tan Valley's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at San Tan Valley’s own scale
6 of the readings below were taken at San Tan Valley's own scale — the 48,508 acres it covers and 174 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- San Tan Valley's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 174 documented contamination sites on the federal record near San Tan Valley, the closest Nitrate record about 0.8 miles out from the town centreFederal environmental registers
- San Tan Valley's boundary and the 48,508 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 ecoregion at San Tan Valley's own centroid, the Sonoran Basin and RangeUS EPA Level III Ecoregions
- Lanternfly survey cells around San Tan Valley checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The 28°F hard-freeze dates — San Tan Valley has no normal of its own, so its county's is the closest measured readfrom Pinal County
- Soil character — no town-scale survey exists, so San Tan Valley's 48,508 acres read through its county's SSURGO summaryfrom Pinal County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Pinal County
- The growing challenges every Arizona grower plans around — written at state scale, so they stay on the state guidefrom Arizona
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Pinal County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among San Tan Valley's 48,508 acreswhy one lot differs from the next →
- Which side of San Tan Valley you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 48,508 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.8 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any San Tan Valley-wide figureread your own land →