San Juan County, in New Mexico, sits in USDA hardiness zone 7a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Well-matched crops include green chile, pecan, pinon pine, and prickly pear, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
San Juan County holds more than one microclimate.
Soils and elevations shift across San Juan 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.
No card required · your full report in seconds
Quick Facts
USDA Zones
7a
Last Hard Freeze (28°F)
Mar 23
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Nov 8
County normal — light frosts arrive a few weeks earlier
County Area
3.5M acres
Hardiness Zone Range
Zone maps are averages across San Juan County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in San Juan County
Across San Juan County, the ground is predominantly Aridisols, where Sheppard, Persayo, and Shiprock are the most extensive named soil series. The soil is generally well drained with a fine sandy loam surface. Topsoil pH runs about 7.6–8.2, slightly alkaline. Rainfall drains through hydrologic group D soils.
Soil order
Aridisols
Drainage
Well drained
Hydric soils
1%
Soil still varies lot by lot — soil types explained.
What Grows in San Juan County
Plants matched to San Juan County's USDA zones 7a — each links to its full growing profile.
Is it too late to plant in San Juan County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 23; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 8 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
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 San Juan County — and how to grow with it.
We checked the federal record across San Juan County — 1,253 documented sites across 6 of the 9 source types we track.
The most significant on record: 18 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
San Juan 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.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Sources Checked
across San Juan County
Severity Distribution
across San Juan County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around San Juan County, two things run higher than the national average — Nitrate (620 sites) and Superfund (18 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in San Juan 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
San Juan 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 San Juan County
Pull a site-specific report for your exact address in San Juan 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 San Juan County, New Mexico
- USDA Hardiness Zones: 7a (USDA PHZM 2023)
- Last Hard Freeze (28°F): Mar 23 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Nov 8 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~230 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 3.5M 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 San Juan 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 San Juan County, New Mexico?
San Juan 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 San Juan County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 23; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 8 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
When does frost risk typically end in San Juan County?
The last hard freeze (28°F) in San Juan County typically lands around Mar 23, 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 San Juan County?
Measured between 28°F hard freezes, San Juan County sees about 230 frost-free days — roughly Mar 23 through Nov 8, 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 San Juan County?
San Juan 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 San Juan County, really?
Officially, San Juan 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 San Juan County?
The federal record around San Juan County runs heavier than most — 1,253 documented sites — 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.
Just moved to San Juan County — what should I know before planting?
Start with three facts. San Juan County sits in USDA zone 7a, which sets what survives winter; the last 28°F hard freeze typically clears around Mar 23, with about 230 frost-free days to work with (NOAA 1991–2020 climate normals); and 1,253 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 San Juan 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.