Fairfield, Idaho, sits in USDA hardiness zone 5a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
A short list that earns its place here — pumpkin, cranberry, lavender, and zucchini — with any one site's soil, sun, and drainage making the final cut.
Even in Fairfield, 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 Fairfield 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 Fairfield — soil, climate, flood, and parcel records. How we handle your address.
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Fairfield — the short answer
Fairfield, Idaho: USDA zone 5a, about 108 days between hard freezes, across 561 acres of city.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 14
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~108
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 561 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 5a is Fairfield's average, not your lot's — a low corner or a tree line moves it. Against Fairfield's 108-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Fairfield
Each reading below is measured for Fairfield itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredFairfield runs about 108 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
MeasuredFairfield sits in USDA hardiness zone 5a.
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 Fairfield is in
Fairfield sits in the Snake River Plain — EPA Level III, inside the wider North American Deserts. That is read at Fairfield's own centroid, and it is not what its county reads: Camas County is mostly Idaho Batholith. The wider page above you is answering a different question about different ground.
What Grows in Fairfield
Every plant below cleared Fairfield's own zone 5a and its 108-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Fairfield?
Almost never — the real question is what to plant next. Cool-season crops can go in from around May 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 29 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 14 — long-season crops need about 90 days of runway, quick greens only 30. In a season this compact, fast finishers and cold-hardy greens do the late work, and garlic tucked in before the freeze repays you next summer.
What's on the federal record near Fairfield
Closest first, within ~10 miles of Fairfield. Listing isn't leaking, and distance isn't exposure.
- 01S 14E 09DBA1Nitrate · 750 ft
- POOLE PAINTINGBrownfields · 2000 ft
- IDAHO ICE CREAM-M&M ServiceUnderground Storage Tanks · 2400 ft
- STEWART SERVICEUnderground Storage Tanks · 0.5 mi
- USFS FAIRFIELD RANGER DIST 1Underground Storage Tanks · 0.5 mi
- CAMAS COUNTY ROAD & BRIDGEUnderground Storage Tanks · 0.5 mi
- SHAKE CREEK GUARD STATIONUnderground Storage Tanks · 0.5 mi
- SIMON FARMS INCUnderground Storage Tanks · 0.5 mi
- USFS FAIRFIELD RANGER DIST 3Underground Storage Tanks · 0.5 mi
- Camas County Airport-west pumpUnderground Storage Tanks · 0.6 mi
- VALLEY SERVICEUnderground Storage Tanks · 0.6 mi
- 01S 14E 11CCC1Nitrate · 1.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Fairfield'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 Fairfield.
Total Sites
55
within ~10 miles of Fairfield
Risk Level
Moderate
Highest-severity
3 mining sites (prospects, none worked)
Sources Checked
within ~10 miles of Fairfield
Severity Distribution
within ~10 miles of Fairfield
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Fairfield, two things run higher than the national average within ~10 miles of Fairfield — Nitrate (36 sites) and Mining (3 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
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 well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Fairfield
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 Fairfield average
Your land is one point inside Fairfield
Everything above resolves to Fairfield as a whole — one PHZM band and one 28°F frost record, read across 561 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 Fairfield Average
Fairfield Average
- ●USDA Zones 5a, averaged across Fairfield
- ●One soil character for all of Fairfield
- ●Frost dates read at Fairfield's scale: May 29 to Sep 14
YOUR Parcel
- ✓Your exact zone, not Fairfield's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Fairfield
Pull a site-specific report for your exact address in Fairfield, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Fairfield averages can't show:
We read public map data around Fairfield — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Fairfield average
How we know this about Fairfield
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 Fairfield’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 Fairfield
When does frost risk typically end in Fairfield?
The last hard freeze (28°F) in Fairfield typically lands around May 29, 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 19.
When is the first frost in Fairfield?
The first hard freeze (28°F) in Fairfield typically arrives around Sep 14, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Aug 31, so the watching starts about Aug 15 — about 108 days after the spring freeze cleared.
How long is the growing season in Fairfield?
Measured between 28°F hard freezes, Fairfield sees about 108 frost-free days — roughly May 29 through Sep 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 19 to Aug 31, about 73 days.
Is the soil safe to grow vegetables in Fairfield?
The federal record around Fairfield shows 55 documented sites, mostly Nitrate entries (36), the nearest Nitrate record about 0.1 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 gardeners stretch the season in Fairfield?
With about 108 frost-free days between hard freezes, Fairfield 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 136 to 164 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 29 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Fairfield's scale — its 5a band and its 108-day season. Your yard writes its own version of Fairfield'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 Fairfield’s own scale
6 of the readings below were taken at Fairfield's own scale — its own ~108-day season between 28°F freezes, the 561 acres it covers and 55 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Fairfield's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Fairfield's own 28°F hard-freeze dates, about May 29 and Sep 14 and the ~108-day span between themNOAA 1991–2020 Climate Normals
- 55 documented contamination sites on the federal record near Fairfield, the closest Nitrate record about 0.1 miles out from the town centreFederal environmental registers
- Fairfield's boundary and the 561 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~108-day seasonGrowable Ground crop-matching engine
- Fairfield sits in the Snake River Plain — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Fairfield's 561 acres read through its county's SSURGO summaryfrom Camas County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Camas County
- The growing challenges every Idaho grower plans around — written at state scale, so they stay on the state guidefrom Idaho
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Camas County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Fairfield's 561 acreswhy one lot differs from the next →
- Which side of Fairfield you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 561 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.1 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 Fairfield-wide figureread your own land →
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