Holly, Colorado, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Crops well matched to these conditions include cabbage, hazelnut, lavender, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Holly, 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 Holly 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 Holly — soil, climate, flood, and parcel records. How we handle your address.
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Holly — the short answer
Holly, Colorado: USDA zone 6a, about 187 days between hard freezes, across 467 acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 16
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~187
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 467 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 6a is Holly's average, not your lot's — a low corner or a tree line moves it. Against Holly's 187-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Holly
Each reading below is measured for Holly itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHolly runs about 187 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
MeasuredHolly 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 Holly is in
Holly sits in the High Plains — EPA Level III, inside the wider Great Plains. That is read at Holly's own centroid, and it is not what its county reads: Prowers County is mostly Southwestern Tablelands. The wider page above you is answering a different question about different ground.
What Grows in Holly
Every plant below cleared Holly's own zone 6a and its 187-day season. Each card opens that plant's Colorado profile. How we score.
Is it too late to plant in Holly?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 19; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 16 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 20 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near Holly
Closest first, within ~10 miles of Holly. Listing isn't leaking, and distance isn't exposure.
- PARA MED HEALTH CNTR/HOLLY NURSING CAREBrownfields · 950 ft
- Holly School District Re-3Underground Storage Tanks · 1000 ft
- JR's Country StoreUnderground Storage Tanks · 1200 ft
- East District Road & BridgeUnderground Storage Tanks · 1700 ft
- CLIFF'S SHAMROCK SERVICEBrownfields · 1700 ft
- Lova M NordykeUnderground Storage Tanks · 1800 ft
- CDOT HollyUnderground Storage Tanks · 2000 ft
- SC02304203DADNitrate · 1.4 mi
- SC02304204BCB USGS 380454102091501Nitrate · 2.4 mi
- SC02304218CBB USGS 380258102113201Nitrate · 3.7 mi
- SC02204226BDA1 USGS 380641102063701Nitrate · 3.9 mi
- SC02404203AABNitrate · 4.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Holly'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 Holly.
Total Sites
33
within ~10 miles of Holly
Risk Level
Low
Highest-severity
1 concentrated animal feeding operation
Sources Checked
within ~10 miles of Holly
Severity Distribution
within ~10 miles of Holly
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Holly, Nitrate runs higher than the national average — 22 sites within ~10 miles of Holly. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Holly
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 Holly average
Your land is one point inside Holly
Everything above resolves to Holly as a whole — one PHZM band and one 28°F frost record, read across 467 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 Holly Average
Holly Average
- ●USDA Zones 6a, averaged across Holly
- ●One soil character for all of Holly
- ●Frost dates read at Holly's scale: Apr 16 to Oct 20
YOUR Parcel
- ✓Your exact zone, not Holly's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Holly
Pull a site-specific report for your exact address in Holly, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Holly averages can't show:
We read public map data around Holly — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Holly average
How we know this about Holly
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 Holly’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 Holly
When does frost risk typically end in Holly?
The last hard freeze (28°F) in Holly typically lands around Apr 16, 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 7.
When is the first frost in Holly?
The first hard freeze (28°F) in Holly typically arrives around Oct 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 6, so the watching starts about Sep 20 — about 187 days after the spring freeze cleared.
How long is the growing season in Holly?
Measured between 28°F hard freezes, Holly sees about 187 frost-free days — roughly Apr 16 through Oct 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 7 to Oct 6, about 152 days.
Is the soil safe to grow vegetables in Holly?
The federal record around Holly is light — 33 documented sites across the 9 federal source types we checked, mostly Nitrate entries (22), the nearest Brownfields 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 Holly?
From about Sep 20 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 20 (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 20. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Holly's scale — its 6a band and its 187-day season. Your yard writes its own version of Holly'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 Holly’s own scale
6 of the readings below were taken at Holly's own scale — its own ~187-day season between 28°F freezes, the 467 acres it covers and 33 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Holly's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Holly's own 28°F hard-freeze dates, about Apr 16 and Oct 20 and the ~187-day span between themNOAA 1991–2020 Climate Normals
- 33 documented contamination sites on the federal record near Holly, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- Holly's boundary and the 467 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~187-day seasonGrowable Ground crop-matching engine
- Holly sits in the High Plains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Holly's 467 acres read through its county's SSURGO summaryfrom Prowers County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Prowers 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 Prowers County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Holly's 467 acreswhy one lot differs from the next →
- Which side of Holly you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 467 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Holly-wide figureread your own land →