La Plata County, in Colorado, sits in USDA hardiness zone 6b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Growers here do well with cabbage, blackberry, california poppy, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
La Plata County lies within the Four Corners / Southwest Colorado — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
La Plata County holds more than one microclimate.
Soils and elevations shift across La Plata 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 La Plata County — soil, climate, flood, and parcel records. How we handle your address.
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La Plata County — the short answer
La Plata County, Colorado: USDA zone 6b, about 168 days between hard freezes, across 1.1M acres.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 2
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 17
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~168
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.1M 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 6b is La Plata County's average, not your lot's — a low corner or a tree line moves it. Against La Plata County's 168-day season, see what your own ground reads.
Heat in La Plata County
Across a year, La Plata County accumulates about 1,840 growing degree days above 50°F, about 8 more than the middle Colorado county — ahead of 32 of Colorado’s 64 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 La Plata County
Across La Plata County, the ground is predominantly Alfisols, where Witt, Zyme, and Needleton are the most extensive named soil series. The soil is generally well drained with a loam surface. Topsoil pH runs about 6.5–7.2, neutral. Rainfall drains through hydrologic group C soils.
Soil order
Alfisols
Drainage
Well drained
Hydric soils
1%
Soil still varies lot by lot — soil types explained.
How the ground varies across La Plata County
The USDA soil survey maps 88% of La Plata County as well drained — but another 4% drains differently: 1% somewhat poorly drained, 1% poorly drained.
Witt is the most extensive named soil at 5% of mapped acres, then Zyme (4%) and Needleton (3%).
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 La Plata County
Each reading below is measured for La Plata 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 La Plata County are well drained, in hydrologic group C — 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 La Plata County runs about pH 6.5–7.2, 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
MeasuredLa Plata County runs about 168 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
MeasuredLa Plata County sits in USDA hardiness zone 6b.
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 La Plata County is in
La Plata County spans 2 EPA Level III ecoregions — Southern Rockies (52%) and Colorado Plateaus (48%). 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 La Plata County
We scored all 1,086 plants against La Plata County's own USDA zone 6b and its own 168-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 Colorado profile.
Is it too late to plant in La Plata 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 Apr 4; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 2 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 17 — 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 gets applied to farmland in La Plata County
USGS estimates 7,463 lb of Glyphosate on La Plata County farmland in 2019, its largest by weight, ahead of Atrazine (2,066 lb) and 2,4-d (1,956 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 La Plata County — and how to grow with it.
We checked the federal record across La Plata County — 486 documented sites across 6 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.
La Plata 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 La Plata County
Closest first, across La Plata County. Listing isn't leaking, and distance isn't exposure.
- Huck Finn ExxonUnderground Storage Tanks · 0.9 mi
- Sky Ridge Convenience StoreUnderground Storage Tanks · 1.1 mi
- US West CommunicationsUnderground Storage Tanks · 1.4 mi
- FORT LEWIS COLLEGEBrownfields · 1.7 mi
- Circle K #256Underground Storage Tanks · 1.8 mi
- Roseberrys Plbg & HeatingUnderground Storage Tanks · 1.8 mi
- La Plata-fairgroundsUnderground Storage Tanks · 1.9 mi
- Durango ArmoryUnderground Storage Tanks · 1.9 mi
- WALGREENS STORE #10371Brownfields · 1.9 mi
- LA PLATA COUNTY FAIRGROUNDS SHOP/ LA PLATA COUNTY GOVERNMENTBrownfields · 1.9 mi
- CITY MARKET 421Brownfields · 1.9 mi
- Mercy Medical CenterUnderground Storage Tanks · 2.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from La Plata 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 La Plata County.
Total Sites
486
across La Plata County
Risk Level
High
Highest-severity
6 Toxics Release Inventory facilities
Sources Checked
across La Plata County
Severity Distribution
across La Plata County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around La Plata County, two things run higher than the national average across La Plata County — Mining (115 sites) and Nitrate (158 sites). That's not a problem with your land — it's information about it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in La Plata 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 La Plata County average
Your land is one point inside La Plata County
Everything above resolves to La Plata County as a whole — one PHZM band and one county frost record, read across 1.1M 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 La Plata County Average
La Plata County Average
- ●USDA Zones 6b, averaged across La Plata County
- ●One soil character for all of La Plata County
- ●Frost dates read at La Plata County's scale: May 2 to Oct 17
YOUR Parcel
- ✓Your exact zone, not La Plata County's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in La Plata County
Pull a site-specific report for your exact address in La Plata County, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that La Plata County averages can't show:
We read public map data around La Plata County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the La Plata County average
How we know this about La Plata 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 La Plata County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about La Plata County
When does frost risk typically end in La Plata County?
The last hard freeze (28°F) in La Plata County typically lands around May 2, 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 23.
How long is the growing season in La Plata County?
Measured between 28°F hard freezes, La Plata County sees about 168 frost-free days — roughly May 2 through Oct 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 23 to Oct 3, about 133 days.
Is the soil safe to grow vegetables in La Plata County?
The federal record around La Plata County runs heavier than most — 486 documented sites, mostly Nitrate entries (158), the nearest Underground Storage Tanks record about 0.9 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 La Plata County's scale — its 6b band and its 168-day season. Your yard writes its own version of La Plata 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 Colorado's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at La Plata County’s own scale
8 of the readings below were taken at La Plata County's own scale — its own ~168-day span between 28°F freezes, the 3 most extensive soil series mapped here and 486 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- La Plata County's own USDA hardiness band, zones 6bUSDA PHZM 2023
- La Plata County's own 28°F hard-freeze dates and its ~168-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in La Plata CountyUSDA NRCS SSURGO
- 486 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 0.9 miles outFederal environmental registers
- La Plata County's boundary and the 1,081,395 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~168-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions La Plata County spans, Southern Rockies the largestUS EPA Level III Ecoregions
- Which agricultural compounds go onto La Plata County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Colorado grower plans around — written at state scale, so they stay on the state guidefrom Colorado
What this page can’t tell you
- How the season shifts across La Plata County — the ~168 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 La Plata County's 1,081,395 acreswhy one lot differs from the next →
- Which of those 486 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 La Plata Countyread your own land →