Los Alamos County, in New Mexico, sits in USDA hardiness zone 7a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
On paper, green chile, pecan, pinon pine, and prickly pear all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Los Alamos County holds more than one microclimate.
Soils and elevations shift across Los Alamos County, so your frost dates and drainage aren't the county average. 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
7a
Last Hard Freeze (28°F)
Apr 5
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Nov 1
County normal — light frosts arrive a few weeks earlier
County Area
70K acres
Hardiness Zone Range
Zone maps are averages across Los Alamos County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in Los Alamos County
Across Los Alamos County, the ground is predominantly Alfisols, where Carjo, Totavi, and Hackroy are the most extensive named soil series. The soil is generally well drained with a bedrock surface. Topsoil pH runs about 7.0, neutral. Rainfall drains through hydrologic group D soils.
Soil order
Alfisols
Drainage
Well drained
Hydric soils
0%
Soil still varies lot by lot — soil types explained.
What Grows in Los Alamos County
Plants matched to Los Alamos County's USDA zones 7a — each links to its full growing profile.
Is it too late to plant in Los Alamos County?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 1 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
Growing Challenges in New Mexico
What an experienced grower plans around here — each one has a move.
Very low rainfall requires irrigation for most crops
High-desert growing starts with the water plan — drip lines, deep mulch, and basins put scarce rain exactly where roots are.
High altitude UV intensity can burn tender transplants
Harden seedlings slowly and shade-cloth their first week out — high-desert sun is stronger than any indoor start prepares them for.
Alkaline soils limit plant selection without amendment
Test first: knowing your actual pH turns 'what won't grow' into a short, workable amendment list.
For cultivar selection, pest pressure, and planting-time guidance specific to New Mexico, the NMSU Cooperative Extension Service is the authoritative local source.
Safe to Grow Here?
What the federal record shows across Los Alamos County — and how to grow with it.
We checked the federal record across Los Alamos County — 165 documented sites across 6 of the 9 source types we track.
The most significant on record: 1 Superfund site. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Los Alamos County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Sources Checked
across Los Alamos County
Severity Distribution
across Los Alamos County
Highest-Severity Sites
Know Before You Grow
- •Underground tanks can leak petroleum products. Soil testing near former gas stations is recommended.
- •Raised beds with imported soil can reduce exposure risk near brownfield sites.
- •Test well water for nitrates if you rely on a private well. Levels above 10 mg/L require treatment.
Check your specific parcel in Los Alamos County
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
Los Alamos County Average
- ●USDA Zones 7a
- ●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 parcel in Los Alamos County
Pull a site-specific report for your exact address in Los Alamos County, New Mexico — 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 Los Alamos County, New Mexico
- USDA Hardiness Zones: 7a (USDA PHZM 2023)
- Last Hard Freeze (28°F): Apr 5 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Nov 1 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~210 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 70K acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. County boundaries: US Census TIGER/Line 2025.
Frost dates here are the Los Alamos County average. Low spots and tree cover move them by days on any one yard — see your exact frost windows.
Frequently Asked Questions
What hardiness zone is Los Alamos County, New Mexico?
Los Alamos County sits in USDA hardiness zone 7a, 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 Los Alamos County?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 1 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
When does frost risk typically end in Los Alamos County?
The last hard freeze (28°F) in Los Alamos County typically lands around Apr 5, 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.
How long is the growing season in Los Alamos County?
Measured between 28°F hard freezes, Los Alamos County sees about 210 frost-free days — roughly Apr 5 through Nov 1, per NOAA 1991–2020 climate normals. Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
What vegetables grow in Los Alamos County?
Los Alamos County's zone 7a supports a wide range — strong performers include Green Chile, Pecan, Pinon Pine, Prickly Pear, and Apache Plume. 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 Los Alamos County, really?
Officially, Los Alamos County sits in USDA zone 7a (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 Los Alamos County?
The federal record around Los Alamos County is a meaningful one — 165 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.
Just moved to Los Alamos County — what should I know before planting?
Start with three facts. Los Alamos County sits in USDA zone 7a, which sets what survives winter; the last 28°F hard freeze typically clears around Apr 5, with about 210 frost-free days to work with (NOAA 1991–2020 climate normals); and 165 documented sites sit on the federal record here, so a soil test before food beds is the smart first step. From there, matching plants to your actual soil and sun is the fun part.
Everything on this page is a Los Alamos County 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.
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.