Jackson County, in Colorado, sits in USDA hardiness zone 4b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
These conditions suit zucchini, cranberry, cilantro, and okra — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Jackson County lies within the Colorado High Country (Central Rockies) — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Jackson County holds more than one microclimate.
Soils and elevations shift across Jackson 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 Jackson County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Jackson County — the short answer
Jackson County, Colorado: USDA zone 4b, about 103 days between hard freezes, across 1.0M acres.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 31
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Sep 11
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~103
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.0M 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 Jackson County's average, not your lot's — a low corner or a tree line moves it. Against Jackson County's 103-day season, see what your own ground reads.
Heat in Jackson County
Across a year, Jackson County accumulates about 604 growing degree days above 50°F, about 1,228 fewer than the middle Colorado county — ahead of 11 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 Jackson County
Across Jackson County, the ground is predominantly Mollisols, where Leighcan, Fluetsch, and Tiagos are the most extensive named soil series. The soil is generally well drained with a loam surface. Topsoil pH runs about 5.9–7.0, slightly acidic. Rainfall drains through hydrologic group C soils.
Soil order
Mollisols
Drainage
Well drained
Hydric soils
11%
Soil still varies lot by lot — soil types explained.
How the ground varies across Jackson County
The USDA soil survey maps 78% of Jackson County as well drained — but another 18% drains differently: 6% somewhat excessively drained, 5% poorly drained.
Leighcan is the most extensive named soil at 7% of mapped acres, then Fluetsch (3%) and Tiagos (2%).
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 Jackson County
Each reading below is measured for Jackson 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 Jackson 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 Jackson County runs about pH 5.9–7.0, 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
MeasuredJackson County runs about 103 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
MeasuredJackson 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 Jackson County is in
Jackson County sits in the Southern Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. One consistent ecological setting across the whole county.
What Grows in Jackson County
We scored all 1,086 plants against Jackson County's own USDA zone 4b and its own 103-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 Jackson 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 May 3; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 31 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 11 — long-season crops need about 90 days of runway, quick greens only 30. When the window is tight, the fall moves are quick ones — baby greens, radishes, and garlic set for next season.
What gets applied to farmland in Jackson County
USGS estimates 3,131 lb of Metolachlor & Metolachlor-s on Jackson County farmland in 2019, its largest by weight, ahead of Metolachlor-s (3,074 lb) and Glyphosate (2,677 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 Jackson County — and how to grow with it.
We checked the federal record across Jackson County — 73 documented sites across 5 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.
There's a meaningful federal record across Jackson 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 Jackson County
Closest first, across Jackson County. Listing isn't leaking, and distance isn't exposure.
- Louisiana Pacific Corp Walden PlantUnderground Storage Tanks · 4.9 mi
- Blanton's Mountain Mart IncUnderground Storage Tanks · 5.1 mi
- Corkle's Mini Mart #2Underground Storage Tanks · 5.1 mi
- North Park Automotive & SupplyUnderground Storage Tanks · 5.1 mi
- Walden FinaUnderground Storage Tanks · 5.2 mi
- Walden WarehouseUnderground Storage Tanks · 5.2 mi
- Leroy SpauldingUnderground Storage Tanks · 5.3 mi
- FAMILY DOLLAR #10708Brownfields · 5.3 mi
- USDA USFS R02 WALDEN WORK CENTER ROUTT NATIONAL FORESTBrownfields · 5.3 mi
- Canadian Strip MineUnderground Storage Tanks · 5.4 mi
- CDOT WaldenUnderground Storage Tanks · 5.4 mi
- Jackson County Road & BridgeUnderground Storage Tanks · 5.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Jackson 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 Jackson County.
Total Sites
73
across Jackson County
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
across Jackson County
Severity Distribution
across Jackson County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Jackson County, Mining runs higher than the national average — 44 sites across Jackson County. 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.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Jackson 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 Jackson County average
Your land is one point inside Jackson County
Everything above resolves to Jackson County as a whole — one PHZM band and one county frost record, read across 1.0M 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 Jackson County Average
Jackson County Average
- ●USDA Zones 4b, averaged across Jackson County
- ●One soil character for all of Jackson County
- ●Frost dates read at Jackson County's scale: May 31 to Sep 11
YOUR Parcel
- ✓Your exact zone, not Jackson County's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Jackson County
Pull a site-specific report for your exact address in Jackson County, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Jackson County averages can't show:
We read public map data around Jackson County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Jackson County average
How we know this about Jackson 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 Jackson County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Jackson County
When does frost risk typically end in Jackson County?
The last hard freeze (28°F) in Jackson County typically lands around May 31, 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 21.
How long is the growing season in Jackson County?
Measured between 28°F hard freezes, Jackson County sees about 103 frost-free days — roughly May 31 through Sep 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 21 to Aug 28, about 68 days.
Is the soil safe to grow vegetables in Jackson County?
The federal record around Jackson County is a meaningful one — 73 documented sites, mostly Mining entries (44), the nearest Underground Storage Tanks record about 4.9 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 Jackson County?
With about 103 frost-free days between hard freezes, Jackson 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 131 to 159 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 31 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Jackson County's scale — its 4b band and its 103-day season. Your yard writes its own version of Jackson 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 Jackson County’s own scale
8 of the readings below were taken at Jackson County's own scale — its own ~103-day span between 28°F freezes, the 3 most extensive soil series mapped here and 73 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Jackson County's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Jackson County's own 28°F hard-freeze dates and its ~103-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Jackson CountyUSDA NRCS SSURGO
- 73 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 4.9 miles outFederal environmental registers
- Jackson County's boundary and the 1,032,783 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~103-day seasonGrowable Ground crop-matching engine
- Jackson County sitting wholly inside the Southern RockiesUS EPA Level III Ecoregions
- Which agricultural compounds go onto Jackson 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 Jackson County — the ~103 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 Jackson County's 1,032,783 acreswhy one lot differs from the next →
- Which of those 73 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 Jackson Countyread your own land →