Coolidge, Arizona, sits in USDA hardiness zone 9a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Crops well matched to these conditions include jalapeno, palo verde, date palm, and prickly pear — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Coolidge, 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 Coolidge 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 Coolidge — soil, climate, flood, and parcel records. How we handle your address.
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Coolidge — the short answer
Coolidge, Arizona: USDA zone 9a, about 327 days between hard freezes, across 53K acres of city.
- USDA zone
- 9a
- 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
- City area
- 53K 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 9a is Coolidge's average, not your lot's — a low corner or a tree line moves it. Against Coolidge's 327-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Coolidge
Each reading below is measured for Coolidge itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsCoolidge runs about 327 days between hard freezes (read from Pinal County, the closest normal to Coolidge) — 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
MeasuredCoolidge sits in USDA hardiness zone 9a.
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 Coolidge is in
Coolidge sits in the Sonoran Basin and Range — EPA Level III, inside the wider North American Deserts. That is read at Coolidge's own centroid rather than borrowed from Pinal County.
What Grows in Coolidge
Plants matched to Coolidge's USDA zones 9a, ordered by how much hardiness margin each has here — the ones with room to spare at both ends of this town's band lead. Each links to its full growing profile.
Is it too late to plant in Coolidge?
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. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
Documented around Coolidge
Survey cells within 31 miles of Coolidge checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 328 miles off. What to watch for.
What's on the federal record near Coolidge
Closest first, within ~10 miles of Coolidge. Listing isn't leaking, and distance isn't exposure.
- D-06-08S04ADC1Nitrate · 2000 ft
- D-06-08S04ADD1Nitrate · 0.5 mi
- HOLLAND PROPERTYUnderground Storage Tanks · 0.8 mi
- STINGERBrownfields · 1.2 mi
- DOUGLAS PROPERTYUnderground Storage Tanks · 1.2 mi
- D-05-08 34DDD1Nitrate · 1.2 mi
- DESERT GARAGEUnderground Storage Tanks · 1.3 mi
- SUNBELT REFINING CO.Toxics Release Inventory · 1.4 mi
- D-06-08N05CBC1Nitrate · 1.6 mi
- COOLIDGE GENERATING STATIONBrownfields · 1.7 mi
- D-06-08S06ABDNitrate · 1.8 mi
- D-05-08 32CDD1Nitrate · 1.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Coolidge'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 Coolidge.
Total Sites
313
within ~10 miles of Coolidge
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Coolidge
Severity Distribution
within ~10 miles of Coolidge
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Coolidge, Nitrate runs higher than the national average — 192 sites within ~10 miles of Coolidge. That's not a problem with your land — it's information about 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).
Check your specific parcel in Coolidge
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 Coolidge average
Your land is one point inside Coolidge
Everything above resolves to Coolidge as a whole — one PHZM band, read across 53K acres, with hard-freeze dates borrowed from Pinal County’s record because no 30-year normal resolves at this city’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 city 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 Coolidge Average
Coolidge Average
- ●USDA Zones 9a, averaged across Coolidge
- ●One soil character for all of Coolidge
- ●Frost dates read at Coolidge's scale: Jan 23 to Dec 16
YOUR Parcel
- ✓Your exact zone, not Coolidge's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Coolidge
Pull a site-specific report for your exact address in Coolidge, Arizona — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Coolidge averages can't show:
We read public map data around Coolidge — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Coolidge average
How we know this about Coolidge
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’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 city grain anywhere on this page — there is no city-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 Coolidge
When does frost risk typically end in Coolidge?
The last hard freeze (28°F) in Coolidge 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 Coolidge?
The first hard freeze (28°F) in Coolidge 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 Coolidge?
Measured between 28°F hard freezes, Coolidge 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 Coolidge?
The federal record around Coolidge is a meaningful one — 313 documented sites, mostly Nitrate entries (192), the nearest Nitrate record about 0.4 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in Coolidge?
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 Coolidge's scale — its 9a band and its 327-day season. Your yard writes its own version of Coolidge'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 Coolidge’s own scale
5 of the readings below were taken at Coolidge's own scale — the 53,423 acres it covers and 313 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- Coolidge's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 313 documented contamination sites on the federal record near Coolidge, the closest Nitrate record about 0.4 miles out from the town centreFederal environmental registers
- Coolidge's boundary and the 53,423 acres inside itUS Census TIGER/Line 2025
- The ecoregion at Coolidge's own centroid, the Sonoran Basin and RangeUS EPA Level III Ecoregions
- Lanternfly survey cells around Coolidge checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The 28°F hard-freeze dates — Coolidge 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 Coolidge's 53,423 acres read through its county's SSURGO summaryfrom Pinal County
- The candidate plant list — Arizona's curated set, filtered to this zone band and re-ordered by how much margin each has herefrom Arizona
- 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 Coolidge's 53,423 acreswhy one lot differs from the next →
- Which side of Coolidge you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 53,423 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.4 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 Coolidge-wide figureread your own land →
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