San Ardo, California, sits in USDA hardiness zone 9a — 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 artichoke, fig, california poppy, and cabbage — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in San Ardo, 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 San Ardo 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 San Ardo — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
San Ardo — the short answer
San Ardo, California: USDA zone 9a, about 317 days between hard freezes, across 287 acres of town.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 27
- Monterey County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 10
- Monterey County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~317
- Monterey County normal — NOAA 1991–2020, nearest to this town
- Town area
- 287 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Monterey County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is San Ardo's average, not your lot's — a low corner or a tree line moves it. Against San Ardo's 317-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in San Ardo
Each reading below is measured for San Ardo itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSan Ardo runs about 317 days between hard freezes (read from Monterey County, the closest normal to San Ardo) — 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
MeasuredSan Ardo sits in USDA hardiness zone 9a.
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 San Ardo is in
San Ardo sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at San Ardo's own centroid rather than borrowed from Monterey County.
What Grows in San Ardo
Every plant below cleared San Ardo's own zone 9a and its 317-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in San Ardo?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Jan 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jan 27 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 10 — 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.
What's on the federal record near San Ardo
Closest first, within ~10 miles of San Ardo. Listing isn't leaking, and distance isn't exposure.
- SAN BERNARDO RANCHOBrownfields · 450 ft
- PACIFIC BELLBrownfields · 500 ft
- CLEAN HARBORSBrownfields · 950 ft
- GAZELLE TRANSPORTATION INCBrownfields · 1000 ft
- SAN BERNARDO RANCHO HQBrownfields · 1000 ft
- SALINAS VALLEY SOLID WASTE AUTHORITYBrownfields · 1100 ft
- KINGS OIL TOOLS INCBrownfields · 2000 ft
- RICH SAND ETHRIDGE COBrownfields · 2100 ft
- COUNTY OF MONTEREY SAN ARDO DISTRICT 4Brownfields · 2200 ft
- SWIFT TECTONICS, INCBrownfields · 2300 ft
- 022S010E17L002MNitrate · 0.8 mi
- CHRISTENSEN & GIANNINIBrownfields · 0.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from San Ardo'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 San Ardo.
Total Sites
56
within ~10 miles of San Ardo
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of San Ardo
Severity Distribution
within ~10 miles of San Ardo
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around San Ardo, two things run higher than the national average within ~10 miles of San Ardo — Brownfields (38 sites) and Nitrate (16 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in San Ardo
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 San Ardo average
Your land is one point inside San Ardo
Everything above resolves to San Ardo as a whole — one PHZM band, read across 287 acres, with hard-freeze dates borrowed from Monterey County’s record because no 30-year normal resolves at this town’s own centroid. 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 San Ardo Average
San Ardo Average
- ●USDA Zones 9a, averaged across San Ardo
- ●One soil character for all of San Ardo
- ●Frost dates read at San Ardo's scale: Jan 27 to Dec 10
YOUR Parcel
- ✓Your exact zone, not San Ardo's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in San Ardo
Pull a site-specific report for your exact address in San Ardo, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that San Ardo averages can't show:
We read public map data around San Ardo — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the San Ardo average
How we know this about San Ardo
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 Monterey County’s record, because none resolves here; 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 San Ardo
When does frost risk typically end in San Ardo?
The last hard freeze (28°F) in San Ardo typically lands around Jan 27, 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 Feb 17.
When is the first frost in San Ardo?
The first hard freeze (28°F) in San Ardo typically arrives around Dec 10, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 26, so the watching starts about Nov 10 — about 317 days after the spring freeze cleared.
How long is the growing season in San Ardo?
Measured between 28°F hard freezes, San Ardo sees about 317 frost-free days — roughly Jan 27 through Dec 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 17 to Nov 26, about 282 days.
Is the soil safe to grow vegetables in San Ardo?
The federal record around San Ardo shows 56 documented sites, mostly Brownfields entries (38), the nearest Brownfields record under a tenth of a mile 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 I protect my plants from frost in San Ardo?
From about Nov 10 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 Dec 10 (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 Dec 10. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at San Ardo's scale — its 9a band and its 317-day season. Your yard writes its own version of San Ardo'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 San Ardo’s own scale
5 of the readings below were taken at San Ardo's own scale — the 287 acres it covers and 56 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- San Ardo's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 56 documented contamination sites on the federal record near San Ardo, the closest Brownfields record under a tenth of a mile out from the town centreFederal environmental registers
- San Ardo's boundary and the 287 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~317-day seasonGrowable Ground crop-matching engine
- The ecoregion at San Ardo's own centroid, the Central California Foothills and Coastal MountainsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — San Ardo has no normal of its own, so its county's is the closest measured readfrom Monterey County
- Soil character — no town-scale survey exists, so San Ardo's 287 acres read through its county's SSURGO summaryfrom Monterey County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Monterey County
- The growing challenges every California grower plans around — written at state scale, so they stay on the state guidefrom California
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Monterey County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among San Ardo's 287 acreswhy one lot differs from the next →
- Which side of San Ardo you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 287 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record under a tenth of a mile 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 San Ardo-wide figureread your own land →