Millard County, in Utah, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
These conditions suit cabbage, blackberry, california poppy, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Millard County holds more than one microclimate.
Soils and elevations shift across Millard County, so your frost dates and drainage aren't the county average. 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 Millard County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Millard County — the short answer
Millard County, Utah: USDA zone 6a, about 167 days between hard freezes, across 4.3M acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 26
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 10
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~167
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 4.3M acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 Millard County's average, not your lot's — a low corner or a tree line moves it. Against Millard County's 167-day season, see what your own ground reads.
Heat in Millard County
Across a year, Millard County accumulates about 2,919 growing degree days above 50°F, about 407 more than the middle Utah county — ahead of 21 of Utah’s 29 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Millard County
Across Millard County, the ground is predominantly Entisols, where Uvada, Yenrab, and Abraham are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 8.2–8.8, strongly alkaline. Rainfall drains through hydrologic group D soils.
Soil order
Entisols
Drainage
Well drained
Hydric soils
14%
Soil still varies lot by lot — soil types explained.
How the ground varies across Millard County
The USDA soil survey maps 57% of Millard County as well drained — but another 40% drains differently: 15% somewhat excessively drained, 9% somewhat poorly drained.
Uvada is the most extensive named soil at 9% of mapped acres, then Yenrab (8%) and Abraham (4%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Millard County
Each reading below is measured for Millard County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Millard County are well drained, in hydrologic group D — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Millard County runs about pH 8.2–8.8, on the alkaline side.
Many vegetables cope, but acid-lovers like blueberries struggle, and iron and manganese lock up above about pH 7.5 — leaves yellow between the veins even in rich soil.
Elemental sulfur and generous organic matter lower pH slowly for the beds that need it; test first so you add only what the soil actually calls for.
USDA NRCS SSURGO
Season length
MeasuredMillard County runs about 167 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
MeasuredMillard County 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 Millard County is in
Millard County spans 2 EPA Level III ecoregions — Central Basin and Range (95%) and Wasatch and Uinta Mountains (5%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Millard County
We scored all 1,086 plants against Millard County's own USDA zone 6a and its own 167-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Utah profile.
Is it too late to plant in Millard County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 29; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 26 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 10 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
Documented around Millard County
- monarch butterfly6 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Millard County
USGS estimates 27,173 lb of Glyphosate on Millard County farmland in 2019, its largest by weight, ahead of 2,4-d (8,560 lb) and Metolachlor-s (6,750 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Millard County — and how to grow with it.
We checked the federal record across Millard County — 536 documented sites across 7 of the 9 source types we track.
The most significant on record: 6 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
Millard County carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Millard County
Closest first, across Millard County. Listing isn't leaking, and distance isn't exposure.
- HelviteMining · 8.1 mi
- BLACK HILLS WELL T23S R12W SEC06 SW1/4 SW1/4Nitrate · 10.4 mi
- Monarch ClaimsMining · 10.5 mi
- Galena MinesMining · 12.9 mi
- AT&T CLEAR LAKE RSUnderground Storage Tanks · 15.2 mi
- FAA - BLACK ROCK RMLR (QRO)Underground Storage Tanks · 16.5 mi
- AT&T CRICKET MTN RDUnderground Storage Tanks · 16.6 mi
- GRAYMONT WESTERN US INCORPORATED- CRICKET MOUNTAIN PLANTToxics Release Inventory · 17.1 mi
- CRICKET MOUNTAIN LIME PLANTUnderground Storage Tanks · 17.1 mi
- MUD HOLE WELL T19S R09W SEC29 NW1/4 SW1/4Nitrate · 17.5 mi
- Rock HammerMining · 18.0 mi
- (C-24-10)21aba- 1Nitrate · 18.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Millard County'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 Millard County.
Total Sites
536
across Millard County
Risk Level
High
Highest-severity
6 Toxics Release Inventory facilities
Sources Checked
across Millard County
Severity Distribution
across Millard County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Millard County, two things run higher than the national average across Millard County — CAFO (27 sites) and Nitrate (326 sites). That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Millard County
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 Millard County average
Your land is one point inside Millard County
Everything above resolves to Millard County as a whole — one PHZM band and one county frost record, read across 4.3M 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 county 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 county average.
Your Lot vs the Millard County Average
Millard County Average
- ●USDA Zones 6a, averaged across Millard County
- ●One soil character for all of Millard County
- ●Frost dates read at Millard County's scale: Apr 26 to Oct 10
YOUR Parcel
- ✓Your exact zone, not Millard County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Millard County
Pull a site-specific report for your exact address in Millard County, Utah — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Millard County averages can't show:
We read public map data around Millard County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Millard County average
How we know this about Millard County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Millard County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Millard County
When does frost risk typically end in Millard County?
The last hard freeze (28°F) in Millard County typically lands around Apr 26, 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 17.
How long is the growing season in Millard County?
Measured between 28°F hard freezes, Millard County sees about 167 frost-free days — roughly Apr 26 through Oct 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 17 to Sep 26, about 132 days.
Is the soil safe to grow vegetables in Millard County?
The federal record around Millard County runs heavier than most — 536 documented sites, mostly Nitrate entries (326), the nearest Mining record about 8.1 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.
Everything above is measured at Millard County's scale — its 6a band and its 167-day season. Your yard writes its own version of Millard County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Utah's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Millard County’s own scale
9 of the readings below were taken at Millard County's own scale — its own ~167-day span between 28°F freezes, the 3 most extensive soil series mapped here and 536 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Millard County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Millard County's own 28°F hard-freeze dates and its ~167-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Millard CountyUSDA NRCS SSURGO
- 536 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Mining record about 8.1 miles outFederal environmental registers
- Millard County's boundary and the 4,342,704 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~167-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Millard County spans, Central Basin and Range the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Millard County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Millard County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Utah grower plans around — written at state scale, so they stay on the state guidefrom Utah
What this page can’t tell you
- How the season shifts across Millard County — the ~167 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Millard County's 4,342,704 acreswhy one lot differs from the next →
- Which of those 536 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Millard Countyread your own land →