Sierra County, in New Mexico, sits in USDA hardiness zone 8b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Reliable performers under these conditions include cabbage, fig, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Sierra County holds more than one microclimate.
Soils and elevations shift across Sierra 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 Sierra County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Sierra County — the short answer
Sierra County, New Mexico: USDA zone 8b, about 260 days between hard freezes, across 2.7M acres.
- USDA zone
- 8b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 4
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 19
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~260
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 2.7M 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 8b is Sierra County's average, not your lot's — a low corner or a tree line moves it. Against Sierra County's 260-day season, see what your own ground reads.
Heat and winter chill in Sierra County
Across a year, Sierra County accumulates about 4,819 growing degree days above 50°F, about 1,646 more than the middle New Mexico county — ahead of 29 of New Mexico’s 33 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.
Winter banks about 1,730 hours below 45°F. Chill is what tells a fruit tree its dormancy is over, and it is set by climate rather than by anything you can build.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Sierra County
Across Sierra County, the ground is predominantly Aridisols, where Nickel, Luzena, and Dona Ana are the most extensive named soil series. The soil is generally well drained with a very gravelly fine sandy loam surface. Topsoil pH runs about 7.7–8.2, moderately alkaline. Rainfall drains through hydrologic group D soils.
Soil order
Aridisols
Drainage
Well drained
Hydric soils
0%
Soil still varies lot by lot — soil types explained.
How the ground varies across Sierra County
The USDA soil survey maps 88% of Sierra County as well drained — but another 5% drains differently: 3% excessively drained, 2% somewhat excessively drained.
Nickel is the most extensive named soil at 15% of mapped acres, then Luzena (7%) and Dona Ana (5%).
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 Sierra County
Each reading below is measured for Sierra 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 Sierra County are well drained, in hydrologic group D — 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 Sierra County runs about pH 7.7–8.2, on the alkaline side.
Many vegetables cope, but acid-lovers like blueberries struggle, and iron and manganese lock up above about pH 7.5 — leaves yellow between the veins even in rich soil.
Elemental sulfur and generous organic matter lower pH slowly for the beds that need it; test first so you add only what the soil actually calls for.
USDA NRCS SSURGO
Season length
MeasuredSierra County runs about 260 days between hard freezes — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredSierra County sits in USDA hardiness zone 8b.
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 Sierra County is in
Sierra County spans 2 EPA Level III ecoregions — Chihuahuan Deserts (74%) and Arizona/New Mexico Mountains (26%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Sierra County
We scored all 1,086 plants against Sierra County's own USDA zone 8b and its own 260-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 New Mexico profile.
Is it too late to plant in Sierra County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Feb 4; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 4 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 19 — long-season crops need about 90 days of runway, quick greens only 30. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
Documented around Sierra County
Survey cells within 31 miles of Sierra County checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 561 miles off. What to watch for.
- monarch butterfly3 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Sierra County
USGS estimates 10,871 lb of Glyphosate on Sierra County farmland in 2019, its largest by weight, ahead of Dicamba (4,898 lb) and 2,4-d (2,730 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 Sierra County — and how to grow with it.
We checked the federal record across Sierra County — 544 documented sites across 7 of the 9 source types we track.
The most significant on record: 3 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Sierra County carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Sierra County
Closest first, across Sierra County. Listing isn't leaking, and distance isn't exposure.
- POWER AND STORAGE DIVISION ELEPHANT BUTTE DAMUnderground Storage Tanks · 2.6 mi
- STEPHEN PIERREUnderground Storage Tanks · 3.0 mi
- 13S.04W.34.400Nitrate · 3.0 mi
- Tingley ProspectMining · 3.0 mi
- BOURGUET DARWIN DUnderground Storage Tanks · 3.0 mi
- THOMAS AND SONSBrownfields · 3.1 mi
- RANDYS QUIK LUBEUnderground Storage Tanks · 3.1 mi
- Illinois GroupMining · 3.1 mi
- UNTIED PARCEL SERVICE - TRUTH OR CONSEQUENCESBrownfields · 3.2 mi
- BULLINGTON ELECTRIC SERVICEUnderground Storage Tanks · 3.3 mi
- White Star VeinMining · 3.3 mi
- SIERRA VISTA HOSPITALUnderground Storage Tanks · 3.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Sierra 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 Sierra County.
Sources Checked
across Sierra County
Severity Distribution
across Sierra County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Sierra County, two things run higher than the national average across Sierra County — Mining (288 sites) and Nitrate (152 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 Sierra 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 Sierra County average
Your land is one point inside Sierra County
Everything above resolves to Sierra County as a whole — one PHZM band and one county frost record, read across 2.7M 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 Sierra County Average
Sierra County Average
- ●USDA Zones 8b, averaged across Sierra County
- ●One soil character for all of Sierra County
- ●Frost dates read at Sierra County's scale: Mar 4 to Nov 19
YOUR Parcel
- ✓Your exact zone, not Sierra County's 8b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Sierra County
Pull a site-specific report for your exact address in Sierra County, New Mexico — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Sierra County averages can't show:
We read public map data around Sierra County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Sierra County average
How we know this about Sierra 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 Sierra County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Sierra County
When does frost risk typically end in Sierra County?
The last hard freeze (28°F) in Sierra County typically lands around Mar 4, 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 Mar 25.
How long is the growing season in Sierra County?
Measured between 28°F hard freezes, Sierra County sees about 260 frost-free days — roughly Mar 4 through Nov 19, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 25 to Nov 5, about 225 days.
Is the soil safe to grow vegetables in Sierra County?
The federal record around Sierra County runs heavier than most — 544 documented sites, mostly Mining entries (288), the nearest Underground Storage Tanks record about 2.6 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Everything above is measured at Sierra County's scale — its 8b band and its 260-day season. Your yard writes its own version of Sierra 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 New Mexico's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Sierra County’s own scale
9 of the readings below were taken at Sierra County's own scale — its own ~260-day span between 28°F freezes, the 3 most extensive soil series mapped here and 544 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Sierra County's own USDA hardiness band, zones 8bUSDA PHZM 2023
- Sierra County's own 28°F hard-freeze dates and its ~260-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Sierra CountyUSDA NRCS SSURGO
- 544 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 2.6 miles outFederal environmental registers
- Sierra County's boundary and the 2,675,974 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8b and a ~260-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Sierra County spans, Chihuahuan Deserts the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Sierra County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Sierra County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every New Mexico grower plans around — written at state scale, so they stay on the state guidefrom New Mexico
What this page can’t tell you
- How the season shifts across Sierra County — the ~260 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 Sierra County's 2,675,974 acreswhy one lot differs from the next →
- Which of those 544 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 Sierra Countyread your own land →