Rich County, in Utah, sits in USDA hardiness zone 4b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Reliable performers under these conditions include okra, cranberry, cilantro, and zucchini; what your own ground favors still comes down to its soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Rich County holds more than one microclimate.
Soils and elevations shift across Rich 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 Rich County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Rich County — the short answer
Rich County, Utah: USDA zone 4b, about 110 days between hard freezes, across 658K acres.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 28
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Sep 15
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~110
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 658K 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 4b is Rich County's average, not your lot's — a low corner or a tree line moves it. Against Rich County's 110-day season, see what your own ground reads.
Heat in Rich County
Across a year, Rich County accumulates about 1,131 growing degree days above 50°F, about 1,381 fewer than the middle Utah county — ahead of 2 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 Rich County
Across Rich County, the ground is predominantly Mollisols, where Pancheri, Kearl, and Duckree are the most extensive named soil series. The soil is generally well drained with a loam surface. Topsoil pH runs about 7.5–8.2, slightly alkaline. Rainfall drains through hydrologic group B soils.
Soil order
Mollisols
Drainage
Well drained
Hydric soils
3%
Soil still varies lot by lot — soil types explained.
How the ground varies across Rich County
The USDA soil survey maps 66% of Rich County as well drained — but another 29% drains differently: 21% somewhat excessively drained, 5% poorly drained.
Pancheri is the most extensive named soil at 7% of mapped acres, then Kearl (7%) and Duckree (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 Rich County
Each reading below is measured for Rich 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 Rich County are well drained, in hydrologic group B — 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 Rich County runs about pH 7.5–8.2, 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
MeasuredRich County runs about 110 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
MeasuredRich County sits in USDA hardiness zone 4b.
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 Rich County is in
Rich County spans 2 EPA Level III ecoregions — Wyoming Basin (73%) and Wasatch and Uinta Mountains (27%). 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 Rich County
We scored all 1,086 plants against Rich County's own USDA zone 4b and its own 110-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 Rich County?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Apr 30; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 28 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 15 — 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 gets applied to farmland in Rich County
USGS estimates 2,592 lb of 2,4-d on Rich County farmland in 2019, its largest by weight, ahead of Chlorpyrifos (1,241 lb) and Glyphosate (942 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 Rich County — and how to grow with it.
We checked the federal record across Rich County — 26 documented sites across 3 of the 9 source types we track.
The most significant on record: 5 mining sites. Historic and active mines that may leach heavy metals like arsenic, lead, and cadmium.
The federal record across Rich County is light. Growing food here starts from a strong position — a quick pass over the map tells you whether any recorded site sits near your land, and if one does, that's information to plant with, not a reason to stop.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Rich County
Closest first, across Rich County. Listing isn't leaking, and distance isn't exposure.
- MAVERIK #160 RANDOLPHUnderground Storage Tanks · 3.5 mi
- UDOT STA. # 137AUnderground Storage Tanks · 4.0 mi
- UDOT STA. #137Underground Storage Tanks · 4.1 mi
- MOUNTAIN MEADOW CAMPUnderground Storage Tanks · 4.5 mi
- WOODRUFF COUNTRY STOREUnderground Storage Tanks · 8.1 mi
- UTAH POWER & LIGHT COMPANYUnderground Storage Tanks · 9.3 mi
- Sioux ClaimMining · 12.2 mi
- Arickaree MineMining · 12.5 mi
- Mandan MineMining · 12.5 mi
- UDOT STA. # 1437 LAKETOWNUnderground Storage Tanks · 14.3 mi
- OLD ROCK STOREUnderground Storage Tanks · 14.3 mi
- CROSSROADS CAFEUnderground Storage Tanks · 14.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Rich 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 Rich County.
Severity Distribution
across Rich County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Rich County, two things run higher than the national average across Rich County — Mining (5 sites) and Underground Storage Tanks (19 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Rich 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 Rich County average
Your land is one point inside Rich County
Everything above resolves to Rich County as a whole — one PHZM band and one county frost record, read across 658K 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 Rich County Average
Rich County Average
- ●USDA Zones 4b, averaged across Rich County
- ●One soil character for all of Rich County
- ●Frost dates read at Rich County's scale: May 28 to Sep 15
YOUR Parcel
- ✓Your exact zone, not Rich County's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Rich County
Pull a site-specific report for your exact address in Rich County, Utah — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Rich County averages can't show:
We read public map data around Rich County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Rich County average
How we know this about Rich 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 Rich County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Rich County
When does frost risk typically end in Rich County?
The last hard freeze (28°F) in Rich County typically lands around May 28, 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 18.
How long is the growing season in Rich County?
Measured between 28°F hard freezes, Rich County sees about 110 frost-free days — roughly May 28 through Sep 15, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 18 to Sep 1, about 75 days.
Is the soil safe to grow vegetables in Rich County?
The federal record around Rich County is light — 26 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (19), the nearest Underground Storage Tanks record about 3.5 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do gardeners stretch the season in Rich County?
With about 110 frost-free days between hard freezes, Rich County 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 138 to 166 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 28 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Rich County's scale — its 4b band and its 110-day season. Your yard writes its own version of Rich 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 Rich County’s own scale
8 of the readings below were taken at Rich County's own scale — its own ~110-day span between 28°F freezes, the 3 most extensive soil series mapped here and 26 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Rich County's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Rich County's own 28°F hard-freeze dates and its ~110-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Rich CountyUSDA NRCS SSURGO
- 26 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 3.5 miles outFederal environmental registers
- Rich County's boundary and the 658,405 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~110-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Rich County spans, Wyoming Basin the largestUS EPA Level III Ecoregions
- Which agricultural compounds go onto Rich 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 Rich County — the ~110 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 Rich County's 658,405 acreswhy one lot differs from the next →
- Which of those 26 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 Rich Countyread your own land →