Hartsel, Colorado, sits in USDA hardiness zones 6a-7b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
These conditions suit colorado blue spruce, tomato, penstemon, and apple — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Hartsel, 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 Hartsel lot. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Quick Facts
USDA Zones
6a-7b
Last Hard Freeze (28°F)
May 22
Town normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Sep 25
Town normal — light frosts arrive a few weeks earlier
Town Area
128 acres
Hardiness Zone Range
Zone maps are averages across Hartsel. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil varies lot by lot — soil types explained.
What Grows in Hartsel
Plants matched to Hartsel's USDA zones 6a-7b — each links to its full growing profile.









Is it too late to plant in Hartsel?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 24; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 22 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 25 — long-season crops need about 90 days of runway, quick greens only 30. Short seasons reward decisiveness — quick-maturing varieties late, hardy greens under cover, and next year’s garlic in the ground before it closes.

Growing Challenges in Colorado
What an experienced grower plans around here — each one has a move.

Low annual rainfall (7-20 inches) means irrigation is essential nearly everywhere
Build the irrigation first — drip plus mulch makes a high-desert garden run on remarkably little water.

High altitude UV and temperature swings stress plants
Harden transplants gradually, shade-cloth their first high-sun week, and keep row covers handy for cold nights.

Very short growing season at elevation (60-90 frost-free days above 8,000 ft)
Above 8,000 feet, count your real frost-free days and choose varieties bred to finish inside them.

Alkaline soils (pH 7.5-8.5) limit acid-loving plants without amendment
A soil test tells you your actual pH — grow acid-lovers in containers of amended mix while the native ground grows everything else.
For cultivar selection, pest pressure, and planting-time guidance specific to Colorado, the Colorado State University Extension is the authoritative local source.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Sources Checked
within ~10 miles of Hartsel
Severity Distribution
within ~10 miles of Hartsel
Highest-Severity Sites

A note from Gnorman
What an experienced grower watches for around here
In and around Hartsel, two things run higher than the national average — Mining (5 sites) and Nitrate (18 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 Hartsel
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Your Specific Parcel Matters
Hartsel Average
- ●USDA Zones 6a-7b
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Hartsel
Pull a site-specific report for your exact address in Hartsel, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Key Growing Facts for Hartsel, Colorado
- USDA Hardiness Zones: 6a-7b (USDA PHZM 2023)
- Last Hard Freeze (28°F): May 22 (town normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Sep 25 (town normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~126 (town normal, NOAA 1991–2020 Climate Normals)
- Land Area: 128 acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. Boundaries: US Census TIGER/Line 2025.
Frequently Asked Questions
What hardiness zone is Hartsel, Colorado?
Hartsel sits in USDA hardiness zones 6a-7b, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
Is it too late to plant in Hartsel?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 24; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 22 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 25 — long-season crops need about 90 days of runway, quick greens only 30. Short seasons reward decisiveness — quick-maturing varieties late, hardy greens under cover, and next year’s garlic in the ground before it closes.
When does frost risk typically end in Hartsel?
The last hard freeze (28°F) in Hartsel typically lands around May 22, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.
When is the first frost in Hartsel?
The first hard freeze (28°F) in Hartsel typically arrives around Sep 25, per NOAA 1991–2020 climate normals — the point most tender summer crops finish. Lighter frosts usually reach a couple of weeks earlier, so watch the forecast from late summer on and harvest or cover tender plants before the first cold night.
What vegetables grow in Hartsel?
Hartsel's zones 6a-7b support a wide range — strong performers include Colorado Blue Spruce, Tomato, Penstemon, Apple, and Peach. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Which hardiness zone is Hartsel, really?
Officially, Hartsel sits in USDA zones 6a-7b (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,112 plants against what's actually there.
Is the soil safe to grow vegetables in Hartsel?
The federal record around Hartsel is a meaningful one — 27 documented sites — 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 Hartsel?
With about 126 frost-free days between hard freezes, Hartsel rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder, cold frames and low tunnels more, and quick-maturing varieties make the arithmetic work. Starting transplants indoors ahead of the May 22 hard-freeze normal stretches the season without touching the calendar.
Everything on this page is a Hartsel average. Your yard writes its own version — we read soil, sun, drainage, and frost at your exact address. Try it for 14 days — no card required.
