Flagstaff, Arizona, sits in USDA hardiness zone 6a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Well-matched crops include cabbage, blackberry, california poppy, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Flagstaff, 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 Flagstaff 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 Flagstaff — soil, climate, flood, and parcel records. How we handle your address.
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Flagstaff — the short answer
Flagstaff, Arizona: USDA zone 6a, about 149 days between hard freezes, across 42K acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 16
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~149
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 42K 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 6a is Flagstaff's average, not your lot's — a low corner or a tree line moves it. Against Flagstaff's 149-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Flagstaff
Each reading below is measured for Flagstaff itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredFlagstaff runs about 149 days between hard freezes — a short growing season.
Long-maturing crops like melons, sweet potatoes, and winter squash can run out of runway before the first hard freeze, ripening late or not at all.
Lead with fast-maturing varieties, and stretch the season on both ends with cold frames, low tunnels, or a greenhouse.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredFlagstaff sits in USDA hardiness zone 6a.
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 Flagstaff is in
Flagstaff sits in the Arizona/New Mexico Mountains — EPA Level III, inside the wider Temperate Sierras. That is read at Flagstaff's own centroid, and it is not what its county reads: Coconino County is mostly Arizona/New Mexico Plateau. The wider page above you is answering a different question about different ground.
What Grows in Flagstaff
Every plant below cleared Flagstaff's own zone 6a and its 149-day season. Each card opens that plant's Arizona profile. How we score.
Is it too late to plant in Flagstaff?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Apr 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 16 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 12 — long-season crops need about 90 days of runway, quick greens only 30. Even here the calendar’s edges hold value: thirty-day greens late in the window, then garlic and a rested bed for spring.
Documented around Flagstaff
Survey cells within 31 miles of Flagstaff checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 347 miles off. What to watch for.
What's on the federal record near Flagstaff
Closest first, within ~10 miles of Flagstaff. Listing isn't leaking, and distance isn't exposure.
- LITTLE AMERICA HOTELUnderground Storage Tanks · 2400 ft
- JACKSONS ENERGY #6784Underground Storage Tanks · 2600 ft
- INTERSTATE MOBILE MARTUnderground Storage Tanks · 2600 ft
- SPEEDWAY STORE #2885Underground Storage Tanks · 0.5 mi
- CHEVRON #9-4155Underground Storage Tanks · 0.5 mi
- FLAGSTAFF HOLIDAY INNUnderground Storage Tanks · 0.5 mi
- PIC-N-RUNUnderground Storage Tanks · 0.6 mi
- PHILIPS INDUSTRIES INC MALTA DIVUnderground Storage Tanks · 0.6 mi
- SAM'S CLUB #6604Underground Storage Tanks · 0.6 mi
- CARTER-CARDLOCK INCUnderground Storage Tanks · 0.6 mi
- JIM BABBITT COLLISIONUnderground Storage Tanks · 0.6 mi
- UPS FLAGSTAFFBrownfields · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Flagstaff'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 Flagstaff.
Total Sites
383
within ~10 miles of Flagstaff
Risk Level
Elevated
Highest-severity
10 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Flagstaff
Severity Distribution
within ~10 miles of Flagstaff
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Flagstaff, Underground Storage Tanks runs higher than the national average — 236 sites within ~10 miles of Flagstaff. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Flagstaff
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 Flagstaff average
Your land is one point inside Flagstaff
Everything above resolves to Flagstaff as a whole — one PHZM band and one 28°F frost record, read across 42K 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 Flagstaff Average
Flagstaff Average
- ●USDA Zones 6a, averaged across Flagstaff
- ●One soil character for all of Flagstaff
- ●Frost dates read at Flagstaff's scale: May 16 to Oct 12
YOUR Parcel
- ✓Your exact zone, not Flagstaff's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Flagstaff
Pull a site-specific report for your exact address in Flagstaff, Arizona — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Flagstaff averages can't show:
We read public map data around Flagstaff — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Flagstaff average
How we know this about Flagstaff
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 Flagstaff’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 Flagstaff
When does frost risk typically end in Flagstaff?
The last hard freeze (28°F) in Flagstaff typically lands around May 16, 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 Jun 6.
When is the first frost in Flagstaff?
The first hard freeze (28°F) in Flagstaff typically arrives around Oct 12, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 28, so the watching starts about Sep 12 — about 149 days after the spring freeze cleared.
How long is the growing season in Flagstaff?
Measured between 28°F hard freezes, Flagstaff sees about 149 frost-free days — roughly May 16 through Oct 12, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 6 to Sep 28, about 114 days.
Is the soil safe to grow vegetables in Flagstaff?
The federal record around Flagstaff is a meaningful one — 383 documented sites, mostly Underground Storage Tanks entries (236), the nearest Underground Storage Tanks record about 0.5 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 gardeners stretch the season in Flagstaff?
With about 149 frost-free days between hard freezes, Flagstaff rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder — on this season that is a working window nearer 177 to 205 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 16 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Flagstaff's scale — its 6a band and its 149-day season. Your yard writes its own version of Flagstaff'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 Flagstaff’s own scale
7 of the readings below were taken at Flagstaff's own scale — its own ~149-day season between 28°F freezes, the 42,250 acres it covers and 383 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Flagstaff's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Flagstaff's own 28°F hard-freeze dates, about May 16 and Oct 12 and the ~149-day span between themNOAA 1991–2020 Climate Normals
- 383 documented contamination sites on the federal record near Flagstaff, the closest Underground Storage Tanks record about 0.5 miles out from the town centreFederal environmental registers
- Flagstaff's boundary and the 42,250 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~149-day seasonGrowable Ground crop-matching engine
- Flagstaff sits in the Arizona/New Mexico Mountains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
- Lanternfly survey cells around Flagstaff 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 Flagstaff's 42,250 acres read through its county's SSURGO summaryfrom Coconino County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Coconino 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 Coconino County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Flagstaff's 42,250 acreswhy one lot differs from the next →
- Which side of Flagstaff you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 42,250 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.5 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 Flagstaff-wide figureread your own land →