Dayton, Idaho, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
The conditions favor cabbage, blackberry, california poppy, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Dayton, 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 Dayton 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 Dayton — soil, climate, flood, and parcel records. How we handle your address.
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Dayton — the short answer
Dayton, Idaho: USDA zone 6a, about 165 days between hard freezes, across 4K acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 11
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~165
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 4K 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 Dayton's average, not your lot's — a low corner or a tree line moves it. Against Dayton's 165-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Dayton
Each reading below is measured for Dayton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDayton runs about 165 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredDayton 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 Dayton is in
Dayton sits in the Central Basin and Range — EPA Level III, inside the wider North American Deserts. That is read at Dayton's own centroid, and it is not what its county reads: Franklin County is mostly Northern Basin and Range. The wider page above you is answering a different question about different ground.
What Grows in Dayton
Every plant below cleared Dayton's own zone 6a and its 165-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Dayton?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Apr 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 29 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 11 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Dayton
Closest first, within ~10 miles of Dayton. Listing isn't leaking, and distance isn't exposure.
- 15S 38E 23BBD1Nitrate · 1600 ft
- LUNDAHL IRONWORKSToxics Release Inventory · 1700 ft
- LUNDAHL IRONWORKSBrownfields · 1700 ft
- DAYTON SECTIONUnderground Storage Tanks · 2500 ft
- JNR FARMSUnderground Storage Tanks · 1.5 mi
- 15S 38E 11BBC1Nitrate · 1.8 mi
- 15S/18E-02BCB1Nitrate · 2.7 mi
- 15S 39E 31CBC1Nitrate · 3.1 mi
- 15S 39E 31ABD1Nitrate · 3.1 mi
- Preston Municipal AirportUnderground Storage Tanks · 4.0 mi
- 15S 39E 09BAB1-DESTROYEDNitrate · 4.3 mi
- 15S 39E 09BAB2Nitrate · 4.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Dayton'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 Dayton.
Total Sites
84
within ~10 miles of Dayton
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Dayton
Severity Distribution
within ~10 miles of Dayton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Dayton, Nitrate runs higher than the national average — 46 sites within ~10 miles of Dayton. 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.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Dayton
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 Dayton average
Your land is one point inside Dayton
Everything above resolves to Dayton as a whole — one PHZM band and one 28°F frost record, read across 4K 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 Dayton Average
Dayton Average
- ●USDA Zones 6a, averaged across Dayton
- ●One soil character for all of Dayton
- ●Frost dates read at Dayton's scale: Apr 29 to Oct 11
YOUR Parcel
- ✓Your exact zone, not Dayton's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Dayton
Pull a site-specific report for your exact address in Dayton, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Dayton averages can't show:
We read public map data around Dayton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Dayton average
How we know this about Dayton
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 Dayton’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 Dayton
When does frost risk typically end in Dayton?
The last hard freeze (28°F) in Dayton typically lands around Apr 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 May 20.
When is the first frost in Dayton?
The first hard freeze (28°F) in Dayton typically arrives around Oct 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 27, so the watching starts about Sep 11 — about 165 days after the spring freeze cleared.
How long is the growing season in Dayton?
Measured between 28°F hard freezes, Dayton sees about 165 frost-free days — roughly Apr 29 through Oct 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 20 to Sep 27, about 130 days.
Is the soil safe to grow vegetables in Dayton?
The federal record around Dayton shows 84 documented sites, mostly Nitrate entries (46), the nearest Nitrate record about 0.3 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 I protect my plants from frost in Dayton?
From about Sep 11 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 Oct 11 (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 Oct 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Dayton's scale — its 6a band and its 165-day season. Your yard writes its own version of Dayton'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 Dayton’s own scale
6 of the readings below were taken at Dayton's own scale — its own ~165-day season between 28°F freezes, the 4,271 acres it covers and 84 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Dayton's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Dayton's own 28°F hard-freeze dates, about Apr 29 and Oct 11 and the ~165-day span between themNOAA 1991–2020 Climate Normals
- 84 documented contamination sites on the federal record near Dayton, the closest Nitrate record about 0.3 miles out from the town centreFederal environmental registers
- Dayton's boundary and the 4,271 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~165-day seasonGrowable Ground crop-matching engine
- Dayton sits in the Central Basin and Range — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Dayton's 4,271 acres read through its county's SSURGO summaryfrom Franklin County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Franklin 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 Franklin County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Dayton's 4,271 acreswhy one lot differs from the next →
- Which side of Dayton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,271 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.3 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 Dayton-wide figureread your own land →
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