Garfield County, in Colorado, sits in USDA hardiness zone 6a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Reliable performers under these conditions include cabbage, blackberry, california poppy, and collard greens; 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
Garfield County holds more than one microclimate.
Soils and elevations shift across Garfield 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 Garfield County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Garfield County — the short answer
Garfield County, Colorado: USDA zone 6a, about 142 days between hard freezes, across 1.9M acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 14
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 3
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~142
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.9M 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 Garfield County's average, not your lot's — a low corner or a tree line moves it. Against Garfield County's 142-day season, see what your own ground reads.
Heat in Garfield County
Across a year, Garfield County accumulates about 1,081 growing degree days above 50°F, about 751 fewer than the middle Colorado county — ahead of 17 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 Garfield County
Across Garfield County, the ground is predominantly Mollisols, where Tosca, Irigul, and Jerry are the most extensive named soil series. The soil is generally well drained with a loam surface. Topsoil pH runs about 6.7–7.6, neutral. Rainfall drains through hydrologic group C soils.
Soil order
Mollisols
Drainage
Well drained
Hydric soils
1%
Soil still varies lot by lot — soil types explained.
How the ground varies across Garfield County
The USDA soil survey maps 90% of Garfield County as well drained — but another 4% drains differently: 2% excessively drained, 1% moderately well drained.
Tosca is the most extensive named soil at 4% of mapped acres, then Irigul (3%) and Jerry (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 Garfield County
Each reading below is measured for Garfield 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 Garfield 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 Garfield County runs about pH 6.7–7.6, 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
MeasuredGarfield County runs about 142 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
MeasuredGarfield 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 Garfield County is in
Garfield County spans 2 EPA Level III ecoregions — Colorado Plateaus (57%) and Southern Rockies (43%). 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 Garfield County
We scored all 1,086 plants against Garfield County's own USDA zone 6a and its own 142-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 Garfield County?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Apr 16; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 14 (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 Garfield County
- monarch butterfly2 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Garfield County
USGS estimates 20,755 lb of Glyphosate on Garfield County farmland in 2019, its largest by weight, ahead of Bromoxynil (4,575 lb) and 2,4-d (3,827 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 Garfield County — and how to grow with it.
We checked the federal record across Garfield County — 353 documented sites across 7 of the 9 source types we track.
The most significant on record: 1 Superfund site (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Garfield 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 Garfield County
Closest first, across Garfield County. Listing isn't leaking, and distance isn't exposure.
- DEVELOPMENT ENGINEERING INCBrownfields · 5.9 mi
- USDA USFS R02 RIFLE RDBrownfields · 6.5 mi
- Johnson ConstructionUnderground Storage Tanks · 6.5 mi
- RIFLE GAS PLANTBrownfields · 7.0 mi
- SIMONS PETROLEUM, INC. - RIFLE BULK PLANTToxics Release Inventory · 7.0 mi
- SIMONS PETROLEUM, INC. - RIFLE BULK PLANTBrownfields · 7.0 mi
- Swallow Oil CoUnderground Storage Tanks · 7.1 mi
- Garfield School District #RE2Underground Storage Tanks · 7.3 mi
- Garfield School District Re-2Underground Storage Tanks · 7.3 mi
- Umetco Minerals CorpUnderground Storage Tanks · 7.3 mi
- GARFIELD SCHOOL DIST RE-2 TRANS DEPT.Brownfields · 7.3 mi
- RIFLE HIGH SCHOOL AUTO SHOPPBrownfields · 7.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Garfield 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 Garfield County.
Total Sites
353
across Garfield County
Risk Level
High
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
across Garfield County
Severity Distribution
across Garfield County
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Garfield 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 Garfield County average
Your land is one point inside Garfield County
Everything above resolves to Garfield County as a whole — one PHZM band and one county frost record, read across 1.9M 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 Garfield County Average
Garfield County Average
- ●USDA Zones 6a, averaged across Garfield County
- ●One soil character for all of Garfield County
- ●Frost dates read at Garfield County's scale: May 14 to Oct 3
YOUR Parcel
- ✓Your exact zone, not Garfield County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Garfield County
Pull a site-specific report for your exact address in Garfield County, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Garfield County averages can't show:
We read public map data around Garfield County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Garfield County average
How we know this about Garfield 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 Garfield County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Garfield County
When does frost risk typically end in Garfield County?
The last hard freeze (28°F) in Garfield County typically lands around May 14, 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 4.
How long is the growing season in Garfield County?
Measured between 28°F hard freezes, Garfield County sees about 142 frost-free days — roughly May 14 through Oct 3, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 4 to Sep 19, about 107 days.
Is the soil safe to grow vegetables in Garfield County?
The federal record around Garfield County runs heavier than most — 353 documented sites, mostly Underground Storage Tanks entries (173), the nearest Brownfields record about 5.9 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.
How do gardeners stretch the season in Garfield County?
With about 142 frost-free days between hard freezes, Garfield 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 170 to 198 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 14 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Garfield County's scale — its 6a band and its 142-day season. Your yard writes its own version of Garfield 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 Garfield County’s own scale
9 of the readings below were taken at Garfield County's own scale — its own ~142-day span between 28°F freezes, the 3 most extensive soil series mapped here and 353 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Garfield County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Garfield County's own 28°F hard-freeze dates and its ~142-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Garfield CountyUSDA NRCS SSURGO
- 353 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Brownfields record about 5.9 miles outFederal environmental registers
- Garfield County's boundary and the 1,886,351 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~142-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Garfield County spans, Colorado Plateaus the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Garfield County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Garfield 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 Garfield County — the ~142 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 Garfield County's 1,886,351 acreswhy one lot differs from the next →
- Which of those 353 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 Garfield Countyread your own land →