Blanca, Colorado, sits in USDA hardiness zone 5a — a zone band wide enough that plant choice, not possibility, is the interesting question.
The conditions favor cabbage, cranberry, lavender, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Blanca, 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 Blanca 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 Blanca — soil, climate, flood, and parcel records. How we handle your address.
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Blanca — the short answer
Blanca, Colorado: USDA zone 5a, about 141 days between hard freezes, across 1K acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~141
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 5a is Blanca's average, not your lot's — a low corner or a tree line moves it. Against Blanca's 141-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Blanca
Each reading below is measured for Blanca itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredBlanca runs about 141 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
MeasuredBlanca sits in USDA hardiness zone 5a.
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 Blanca is in
Blanca sits in the Arizona/New Mexico Plateau — EPA Level III, inside the wider North American Deserts. That is read at Blanca's own centroid rather than borrowed from Costilla County.
What Grows in Blanca
Every plant below cleared Blanca's own zone 5a and its 141-day season. Each card opens that plant's Colorado profile. How we score.
Is it too late to plant in Blanca?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Apr 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 12 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 30 — 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.
What's on the federal record near Blanca
Closest first, within ~10 miles of Blanca. Listing isn't leaking, and distance isn't exposure.
- Blanca R V ParkUnderground Storage Tanks · 1700 ft
- Blanca EquipmentUnderground Storage Tanks · 0.7 mi
- CC03007311ADD1Nitrate · 1.2 mi
- CC03007324DDDNitrate · 2.0 mi
- Sierra Grande Schools R-30Underground Storage Tanks · 3.1 mi
- Navajo Trail ChevronUnderground Storage Tanks · 4.2 mi
- Fort Garland YardUnderground Storage Tanks · 4.2 mi
- Ute Cafe & Conoco Hwy 160Underground Storage Tanks · 4.2 mi
- Alta Convenience #3205Underground Storage Tanks · 4.5 mi
- High Altitude ConvenienceUnderground Storage Tanks · 4.6 mi
- CDOT Fort GarlandUnderground Storage Tanks · 4.7 mi
- Glen WiescampUnderground Storage Tanks · 4.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Blanca'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 Blanca.
Sources Checked
within ~10 miles of Blanca
Severity Distribution
within ~10 miles of Blanca
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Blanca, two things run higher than the national average within ~10 miles of Blanca — Mining (7 sites) and Nitrate (12 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around 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 Blanca
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 Blanca average
Your land is one point inside Blanca
Everything above resolves to Blanca as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Blanca Average
Blanca Average
- ●USDA Zones 5a, averaged across Blanca
- ●One soil character for all of Blanca
- ●Frost dates read at Blanca's scale: May 12 to Sep 30
YOUR Parcel
- ✓Your exact zone, not Blanca's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Blanca
Pull a site-specific report for your exact address in Blanca, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Blanca averages can't show:
We read public map data around Blanca — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Blanca average
How we know this about Blanca
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 Blanca’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 Blanca
When does frost risk typically end in Blanca?
The last hard freeze (28°F) in Blanca typically lands around May 12, 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 2.
When is the first frost in Blanca?
The first hard freeze (28°F) in Blanca typically arrives around Sep 30, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 16, so the watching starts about Aug 31 — about 141 days after the spring freeze cleared.
How long is the growing season in Blanca?
Measured between 28°F hard freezes, Blanca sees about 141 frost-free days — roughly May 12 through Sep 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 2 to Sep 16, about 106 days.
Is the soil safe to grow vegetables in Blanca?
The federal record around Blanca shows 29 documented sites, mostly Nitrate entries (12), the nearest Underground Storage Tanks record about 0.3 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do gardeners stretch the season in Blanca?
With about 141 frost-free days between hard freezes, Blanca 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 169 to 197 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 12 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Blanca's scale — its 5a band and its 141-day season. Your yard writes its own version of Blanca'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 Blanca’s own scale
6 of the readings below were taken at Blanca's own scale — its own ~141-day season between 28°F freezes, the 1,173 acres it covers and 29 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Blanca's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Blanca's own 28°F hard-freeze dates, about May 12 and Sep 30 and the ~141-day span between themNOAA 1991–2020 Climate Normals
- 29 documented contamination sites on the federal record near Blanca, the closest Underground Storage Tanks record about 0.3 miles out from the town centreFederal environmental registers
- Blanca's boundary and the 1,173 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~141-day seasonGrowable Ground crop-matching engine
- The ecoregion at Blanca's own centroid, the Arizona/New Mexico PlateauUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Blanca's 1,173 acres read through its county's SSURGO summaryfrom Costilla County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Costilla 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 Costilla County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Blanca's 1,173 acreswhy one lot differs from the next →
- Which side of Blanca you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,173 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.3 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 Blanca-wide figureread your own land →
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