Flagler, Colorado, sits in USDA hardiness zone 5b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Growers here do well with cabbage, cranberry, lavender, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Flagler, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Flagler lot. 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 Flagler — soil, climate, flood, and parcel records. How we handle your address.
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Flagler — the short answer
Flagler, Colorado: USDA zone 5b, about 165 days between hard freezes, across 913 acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~165
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 913 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 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 5b is Flagler's average, not your lot's — a low corner or a tree line moves it. Against Flagler's 165-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Flagler
Each reading below is measured for Flagler itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredFlagler runs about 165 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
MeasuredFlagler sits in USDA hardiness zone 5b.
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 Flagler is in
Flagler sits in the High Plains — EPA Level III, inside the wider Great Plains. That is read at Flagler's own centroid rather than borrowed from Kit Carson County.
What Grows in Flagler
Every plant below cleared Flagler's own zone 5b and its 165-day season. Each card opens that plant's Colorado profile. How we score.
Is it too late to plant in Flagler?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Apr 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 30 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 12 — 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's on the federal record near Flagler
Closest first, within ~10 miles of Flagler. Listing isn't leaking, and distance isn't exposure.
- Dwight ClemmonsUnderground Storage Tanks · 850 ft
- Kit Carson County District #3Underground Storage Tanks · 950 ft
- K C Electric AssociationUnderground Storage Tanks · 1500 ft
- Flagler Farmers Co-opUnderground Storage Tanks · 1700 ft
- SC00905102ABC2Nitrate · 1800 ft
- Colorado Bird Seed PackagingUnderground Storage Tanks · 2000 ft
- Arriba-flagler ConsolidatedUnderground Storage Tanks · 2300 ft
- SC00905102ABCNitrate · 2400 ft
- LP Gas ServiceUnderground Storage Tanks · 0.6 mi
- Loaf N Jug #66Underground Storage Tanks · 0.6 mi
- Moss Standard ServiceUnderground Storage Tanks · 0.7 mi
- Flagler Aerial SprayingUnderground Storage Tanks · 1.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Flagler'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 Flagler.
Sources Checked
within ~10 miles of Flagler
Severity Distribution
within ~10 miles of Flagler
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
Check your specific parcel in Flagler
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 Flagler average
Your land is one point inside Flagler
Everything above resolves to Flagler as a whole — one PHZM band and one 28°F frost record, read across 913 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 town 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 local average.
Your Lot vs the Flagler Average
Flagler Average
- ●USDA Zones 5b, averaged across Flagler
- ●One soil character for all of Flagler
- ●Frost dates read at Flagler's scale: Apr 30 to Oct 12
YOUR Parcel
- ✓Your exact zone, not Flagler's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Flagler
Pull a site-specific report for your exact address in Flagler, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Flagler averages can't show:
We read public map data around Flagler — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Flagler average
How we know this about Flagler
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Flagler’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Flagler
When does frost risk typically end in Flagler?
The last hard freeze (28°F) in Flagler typically lands around Apr 30, 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 21.
When is the first frost in Flagler?
The first hard freeze (28°F) in Flagler typically arrives around Oct 12, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 28, so the watching starts about Sep 12 — about 165 days after the spring freeze cleared.
How long is the growing season in Flagler?
Measured between 28°F hard freezes, Flagler sees about 165 frost-free days — roughly Apr 30 through Oct 12, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 21 to Sep 28, about 130 days.
Is the soil safe to grow vegetables in Flagler?
The federal record around Flagler is light — 22 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (15), the nearest Underground Storage Tanks record about 0.2 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 I protect my plants from frost in Flagler?
From about Sep 12 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 12 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 12. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Flagler's scale — its 5b band and its 165-day season. Your yard writes its own version of Flagler's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Flagler’s own scale
6 of the readings below were taken at Flagler's own scale — its own ~165-day season between 28°F freezes, the 913 acres it covers and 22 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Flagler's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Flagler's own 28°F hard-freeze dates, about Apr 30 and Oct 12 and the ~165-day span between themNOAA 1991–2020 Climate Normals
- 22 documented contamination sites on the federal record near Flagler, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Flagler's boundary and the 913 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~165-day seasonGrowable Ground crop-matching engine
- The ecoregion at Flagler's own centroid, the High PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Flagler's 913 acres read through its county's SSURGO summaryfrom Kit Carson County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Kit Carson County
- The growing challenges every Colorado grower plans around — written at state scale, so they stay on the state guidefrom Colorado
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Kit Carson County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Flagler's 913 acreswhy one lot differs from the next →
- Which side of Flagler you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 913 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Flagler-wide figureread your own land →
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