Crook County, in Wyoming, 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.
Crops well matched to these conditions include cabbage, cranberry, lavender, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Crook County holds more than one microclimate.
Soils and elevations shift across Crook 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 Crook County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Crook County — the short answer
Crook County, Wyoming: USDA zone 5a, about 146 days between hard freezes, across 1.8M acres.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 10
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 3
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~146
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.8M 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 5a is Crook County's average, not your lot's — a low corner or a tree line moves it. Against Crook County's 146-day season, see what your own ground reads.
Heat in Crook County
Across a year, Crook County accumulates about 1,742 growing degree days above 50°F, about 132 fewer than the middle Wyoming county — ahead of 8 of Wyoming’s 23 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 Crook County
Across Crook County, the ground is predominantly Entisols, where Louviers, Samsil, and Grummit are the most extensive named soil series. The soil is generally well drained with a loam surface. Topsoil pH runs about 6.7–7.7, neutral. Rainfall drains through hydrologic group D soils.
Soil order
Entisols
Drainage
Well drained
Prime farmland
3%
Hydric soils
0%
Soil still varies lot by lot — soil types explained.
How the ground varies across Crook County
The USDA soil survey maps 93% of Crook County as well drained — but another 5% drains differently: 3% excessively drained, 1% somewhat excessively drained.
Louviers is the most extensive named soil at 6% of mapped acres, then Samsil (4%) and Grummit (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 Crook County
Each reading below is measured for Crook 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 Crook 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 Crook County runs about pH 6.7–7.7, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredCrook County runs about 146 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
MeasuredCrook County 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 Crook County is in
Crook County spans 2 EPA Level III ecoregions — Middle Rockies (65%) and Northwestern Great Plains (35%). 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 Crook County
We scored all 1,086 plants against Crook County's own USDA zone 5a and its own 146-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 Wyoming profile.
Is it too late to plant in Crook County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 10 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 3 — 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.
Documented around Crook County
- monarch butterfly4 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Crook County
USGS estimates 17,018 lb of Glyphosate on Crook County farmland in 2019, its largest by weight, ahead of 2,4-d (11,099 lb) and Dicamba (5,102 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 Crook County — and how to grow with it.
We checked the federal record across Crook County — 232 documented sites across 6 of the 9 source types we track.
The most significant on record: 4 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Crook County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Crook County
Closest first, across Crook County. Listing isn't leaking, and distance isn't exposure.
- 54-065-13ba 01Nitrate · 6.2 mi
- Fort Devils TowerUnderground Storage Tanks · 6.3 mi
- 53-065-17bac01Nitrate · 6.3 mi
- Tower Valley Ag SupplyUnderground Storage Tanks · 6.5 mi
- Devils Tower Trading PostUnderground Storage Tanks · 6.5 mi
- 54-065-12daa01Nitrate · 6.5 mi
- 54-065-12dab01Nitrate · 6.5 mi
- 54-064-07bc 01Nitrate · 6.6 mi
- 53-065-07dda01Nitrate · 6.7 mi
- WY Department of TransportationUnderground Storage Tanks · 6.8 mi
- Henry L. NeimanUnderground Storage Tanks · 6.8 mi
- 54-065-12aac01Nitrate · 6.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Crook 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 Crook County.
Total Sites
232
across Crook County
Risk Level
Elevated
Highest-severity
4 Superfund sites (none NPL-listed)
Sources Checked
across Crook County
Severity Distribution
across Crook County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Crook County, two things run higher than the national average across Crook County — Nitrate (150 sites) and Superfund (4 sites). That's not a problem with your land — it's information about it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Crook 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 Crook County average
Your land is one point inside Crook County
Everything above resolves to Crook County as a whole — one PHZM band and one county frost record, read across 1.8M 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 Crook County Average
Crook County Average
- ●USDA Zones 5a, averaged across Crook County
- ●One soil character for all of Crook County
- ●Frost dates read at Crook County's scale: May 10 to Oct 3
YOUR Parcel
- ✓Your exact zone, not Crook County's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Crook County
Pull a site-specific report for your exact address in Crook County, Wyoming — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Crook County averages can't show:
We read public map data around Crook County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Crook County average
How we know this about Crook 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 Crook County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Crook County
When does frost risk typically end in Crook County?
The last hard freeze (28°F) in Crook County typically lands around May 10, 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 31.
How long is the growing season in Crook County?
Measured between 28°F hard freezes, Crook County sees about 146 frost-free days — roughly May 10 through Oct 3, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 31 to Sep 19, about 111 days.
Is the soil safe to grow vegetables in Crook County?
The federal record around Crook County is a meaningful one — 232 documented sites, mostly Nitrate entries (150), the nearest Nitrate record about 6.2 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 Crook County?
With about 146 frost-free days between hard freezes, Crook 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 174 to 202 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 10 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Crook County's scale — its 5a band and its 146-day season. Your yard writes its own version of Crook 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 Wyoming's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Crook County’s own scale
9 of the readings below were taken at Crook County's own scale — its own ~146-day span between 28°F freezes, the 3 most extensive soil series mapped here and 232 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Crook County's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Crook County's own 28°F hard-freeze dates and its ~146-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Crook CountyUSDA NRCS SSURGO
- 232 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 6.2 miles outFederal environmental registers
- Crook County's boundary and the 1,826,866 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~146-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Crook County spans, Middle Rockies the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Crook County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Crook County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Wyoming grower plans around — written at state scale, so they stay on the state guidefrom Wyoming
What this page can’t tell you
- How the season shifts across Crook County — the ~146 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 Crook County's 1,826,866 acreswhy one lot differs from the next →
- Which of those 232 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 Crook Countyread your own land →