Duncan, Arizona, sits in USDA hardiness zone 8a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Among the crops suited to this profile: cabbage, fig, california poppy, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Duncan, 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 Duncan 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 Duncan — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Duncan — the short answer
Duncan, Arizona: USDA zone 8a, about 245 days between hard freezes, across 1K acres of town.
- USDA zone
- 8a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 17
- 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
- ~245
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 Duncan's average, not your lot's — a low corner or a tree line moves it. Against Duncan's 245-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Duncan
Each reading below is measured for Duncan itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDuncan runs about 245 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
MeasuredDuncan 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 Duncan is in
Duncan sits in the Chihuahuan Deserts — EPA Level III, inside the wider North American Deserts. That is read at Duncan's own centroid, and it is not what its county reads: Greenlee County is mostly Arizona/New Mexico Mountains. The wider page above you is answering a different question about different ground.
What Grows in Duncan
Every plant below cleared Duncan's own zone 8a and its 245-day season. Each card opens that plant's Arizona profile. How we score.
Is it too late to plant in Duncan?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Feb 17; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 17 (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. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
Documented around Duncan
Survey cells within 31 miles of Duncan checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 470 miles off. What to watch for.
What's on the federal record near Duncan
Closest first, within ~10 miles of Duncan. Listing isn't leaking, and distance isn't exposure.
- GREENLEE COUNTY - DUNCAN YARDUnderground Storage Tanks · 0.8 mi
- FAMILY DOLLAR #9386Brownfields · 1.3 mi
- DUNCAN VALLEY ELECTRIC COOPUnderground Storage Tanks · 1.6 mi
- CROTTS TRUCKINGBrownfields · 1.7 mi
- PETERSON'S CIRCLE R CONVENIENCEUnderground Storage Tanks · 2.1 mi
- DUNCAN HIGH SCHOOLUnderground Storage Tanks · 2.1 mi
- WHITE'S CHEVRONUnderground Storage Tanks · 2.2 mi
- STAGE STOP MINI MARKETUnderground Storage Tanks · 2.2 mi
- 500-30-004Underground Storage Tanks · 2.3 mi
- WATERS PROPERTYUnderground Storage Tanks · 2.3 mi
- CHAPARREL STOREUnderground Storage Tanks · 2.5 mi
- GREENLEE COUNTY APN 500-51-055Underground Storage Tanks · 2.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Duncan'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 Duncan.
Sources Checked
within ~10 miles of Duncan
Severity Distribution
within ~10 miles of Duncan
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Duncan, Mining runs higher than the national average — 18 sites within ~10 miles of Duncan. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Duncan
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 Duncan average
Your land is one point inside Duncan
Everything above resolves to Duncan as a whole — one PHZM band and one 28°F frost record, read across 1K 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 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 Duncan Average
Duncan Average
- ●USDA Zones 8a, averaged across Duncan
- ●One soil character for all of Duncan
- ●Frost dates read at Duncan's scale: Mar 17 to Nov 17
YOUR Parcel
- ✓Your exact zone, not Duncan's 8a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Duncan
Pull a site-specific report for your exact address in Duncan, Arizona — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Duncan averages can't show:
We read public map data around Duncan — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Duncan average
How we know this about Duncan
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 Duncan’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 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 Duncan
When does frost risk typically end in Duncan?
The last hard freeze (28°F) in Duncan typically lands around Mar 17, 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 Apr 7.
When is the first frost in Duncan?
The first hard freeze (28°F) in Duncan 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 245 days after the spring freeze cleared.
How long is the growing season in Duncan?
Measured between 28°F hard freezes, Duncan sees about 245 frost-free days — roughly Mar 17 through Nov 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 7 to Nov 3, about 210 days.
Is the soil safe to grow vegetables in Duncan?
The federal record around Duncan runs heavier than most — 36 documented sites, mostly Mining entries (18), the nearest Underground Storage Tanks record about 0.8 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.
How do I protect my plants from frost in Duncan?
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 Duncan's scale — its 8a band and its 245-day season. Your yard writes its own version of Duncan'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 Duncan’s own scale
7 of the readings below were taken at Duncan's own scale — its own ~245-day season between 28°F freezes, the 1,377 acres it covers and 36 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Duncan's own USDA hardiness band, zones 8aUSDA PHZM 2023
- Duncan's own 28°F hard-freeze dates, about Mar 17 and Nov 17 and the ~245-day span between themNOAA 1991–2020 Climate Normals
- 36 documented contamination sites on the federal record near Duncan, the closest Underground Storage Tanks record about 0.8 miles out from the town centreFederal environmental registers
- Duncan's boundary and the 1,377 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8a and a ~245-day seasonGrowable Ground crop-matching engine
- Duncan sits in the Chihuahuan Deserts — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
- Lanternfly survey cells around Duncan 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 Duncan's 1,377 acres read through its county's SSURGO summaryfrom Greenlee County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Greenlee 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 Greenlee County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Duncan's 1,377 acreswhy one lot differs from the next →
- Which side of Duncan you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,377 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Duncan-wide figureread your own land →
More in Arizona
Wider growing context
What grows across ArizonaDuncan sits outside our named growing regions, so Arizona as a whole is its closest context here.