Douglas, Arizona, sits in USDA hardiness zone 8a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
On paper, cabbage, fig, california poppy, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Douglas, 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 Douglas 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 Douglas — soil, climate, flood, and parcel records. How we handle your address.
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Douglas — the short answer
Douglas, Arizona: USDA zone 8a, about 252 days between hard freezes, across 6K acres of city.
- USDA zone
- 8a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~252
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 6K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 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 8a is Douglas's average, not your lot's — a low corner or a tree line moves it. Against Douglas's 252-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Douglas
Each reading below is measured for Douglas itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDouglas runs about 252 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredDouglas sits in USDA hardiness zone 8a.
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 Douglas is in
Douglas sits in the Madrean Archipelago — EPA Level III, inside the wider Southern Semi-arid Highlands. That is read at Douglas's own centroid rather than borrowed from Cochise County.
What Grows in Douglas
Every plant below cleared Douglas's own zone 8a and its 252-day season. Each card opens that plant's Arizona profile. How we score.
Is it too late to plant in Douglas?
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 Feb 10; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 10 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 17 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
Documented around Douglas
Survey cells within 31 miles of Douglas checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 462 miles off. What to watch for.
What's on the federal record near Douglas
Closest first, within ~10 miles of Douglas. Listing isn't leaking, and distance isn't exposure.
- CITY OF DOULGAS - MUNICIPAL GOLF COURSEUnderground Storage Tanks · 1.7 mi
- COCHISE COUNTY HIGHWAY ROADYARD-DOUGLAS AREAUnderground Storage Tanks · 1.9 mi
- USDA DOUGLAS RANGER DISTRICTUnderground Storage Tanks · 2.4 mi
- USDOJ INS - BORDER PATROLUnderground Storage Tanks · 2.5 mi
- DOUGLAS TURBINESUnderground Storage Tanks · 2.5 mi
- PAISANO HYDROMET CORP LTDUnderground Storage Tanks · 2.5 mi
- APSUnderground Storage Tanks · 2.6 mi
- ADOT - DOUGLASUnderground Storage Tanks · 3.0 mi
- KDAP INC STUDIOUnderground Storage Tanks · 3.1 mi
- GATES PAVINGUnderground Storage Tanks · 3.1 mi
- MADDOX & SONS INCUnderground Storage Tanks · 3.2 mi
- JENNEY FLEIGHT LINE INCUnderground Storage Tanks · 3.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Douglas'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 Douglas.
Total Sites
110
within ~10 miles of Douglas
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Douglas
Severity Distribution
within ~10 miles of Douglas
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Douglas, Nitrate runs higher than the national average — 38 sites within ~10 miles of Douglas. 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 Douglas
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 Douglas average
Your land is one point inside Douglas
Everything above resolves to Douglas as a whole — one PHZM band and one 28°F frost record, read across 6K 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 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 Douglas Average
Douglas Average
- ●USDA Zones 8a, averaged across Douglas
- ●One soil character for all of Douglas
- ●Frost dates read at Douglas's scale: Mar 10 to Nov 17
YOUR Parcel
- ✓Your exact zone, not Douglas's 8a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Douglas
Pull a site-specific report for your exact address in Douglas, Arizona — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Douglas averages can't show:
We read public map data around Douglas — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Douglas average
How we know this about Douglas
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 Douglas’s own record; 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 Douglas
When does frost risk typically end in Douglas?
The last hard freeze (28°F) in Douglas typically lands around Mar 10, 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 Mar 31.
When is the first frost in Douglas?
The first hard freeze (28°F) in Douglas typically arrives around Nov 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 3, so the watching starts about Oct 18 — about 252 days after the spring freeze cleared.
How long is the growing season in Douglas?
Measured between 28°F hard freezes, Douglas sees about 252 frost-free days — roughly Mar 10 through Nov 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 31 to Nov 3, about 217 days.
Is the soil safe to grow vegetables in Douglas?
The federal record around Douglas is a meaningful one — 110 documented sites, mostly Underground Storage Tanks entries (58), the nearest Underground Storage Tanks record about 1.7 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 Douglas?
From about Oct 18 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 Nov 17 (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 Nov 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Douglas's scale — its 8a band and its 252-day season. Your yard writes its own version of Douglas'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 Douglas’s own scale
7 of the readings below were taken at Douglas's own scale — its own ~252-day season between 28°F freezes, the 6,388 acres it covers and 110 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Douglas's own USDA hardiness band, zones 8aUSDA PHZM 2023
- Douglas's own 28°F hard-freeze dates, about Mar 10 and Nov 17 and the ~252-day span between themNOAA 1991–2020 Climate Normals
- 110 documented contamination sites on the federal record near Douglas, the closest Underground Storage Tanks record about 1.7 miles out from the town centreFederal environmental registers
- Douglas's boundary and the 6,388 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8a and a ~252-day seasonGrowable Ground crop-matching engine
- The ecoregion at Douglas's own centroid, the Madrean ArchipelagoUS EPA Level III Ecoregions
- Lanternfly survey cells around Douglas checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Douglas's 6,388 acres read through its county's SSURGO summaryfrom Cochise County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Cochise 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 Cochise County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Douglas's 6,388 acreswhy one lot differs from the next →
- Which side of Douglas you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 6,388 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 1.7 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 Douglas-wide figureread your own land →
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