San Carlos, California, sits in USDA hardiness zone 10a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Expect artichoke, meyer lemon, california poppy, and cabbage to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in San Carlos, 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 Carlos 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 Carlos — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
San Carlos — the short answer
San Carlos, California: USDA zone 10a, no 28°F killing freeze on record — the season is year-round, across 3K acres of city.
- USDA zone
- 10a
- USDA PHZM 2023
- Killing freeze
- None on record
- NOAA RCC ACIS 1991–2020, this town’s own record
- City area
- 3K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. The year-round finding is measured — a 30-year record with no 28°F killing freeze in it — never inferred from missing dates.
Hardiness Zone Range
Zone 10a is San Carlos's average, not your lot's — a low corner or a tree line moves it. Against San Carlos's no killing freeze on record, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in San Carlos
Each reading below is measured for San Carlos itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Winter hardiness
MeasuredSan Carlos sits in USDA hardiness zone 10a.
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 Carlos is in
San Carlos sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at San Carlos's own centroid, and it is not what its county reads: San Mateo County is mostly Coast Range. The wider page above you is answering a different question about different ground.
What Grows in San Carlos
Every plant below cleared San Carlos's own zone 10a. Each card opens that plant's California profile. How we score.
Documented around San Carlos
Spotted lanternfly documented 17 miles from San Carlos, first recorded 2023. What to watch for.
What's on the federal record near San Carlos
Closest first, within ~10 miles of San Carlos. Listing isn't leaking, and distance isn't exposure.
- GARRETT TORRESBrownfields · 200 ft
- LEI WANGBrownfields · 650 ft
- BRAD L HART DDSBrownfields · 1200 ft
- CHAMI KANGBrownfields · 1400 ft
- CALIFORNIA WATER SERVICE - SAN CARLOSPFAS · 1700 ft
- CITY OF REDWOOD CITYPFAS · 1700 ft
- DIGNITY HEALTH MEDICAL GROUP - SEQUOIABrownfields · 1700 ft
- ELAINE TIMMBrownfields · 1900 ft
- KAREN BILLECIBrownfields · 2400 ft
- CALIFORNIA WATER SVC CO MPS BEVERLY TANKBrownfields · 2500 ft
- CEDAR STREET RAD SOURCESSuperfund · 2600 ft
- MARCOS & MARCOS DDSBrownfields · 0.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from San Carlos'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 Carlos.
Sources Checked
within ~10 miles of San Carlos
Severity Distribution
within ~10 miles of San Carlos
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around San Carlos, Brownfields runs higher than the national average — 3,498 sites within ~10 miles of San Carlos. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in San Carlos
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 Carlos average
Your land is one point inside San Carlos
Everything above resolves to San Carlos as a whole — one PHZM band and one 28°F frost record, read across 3K 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 city 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 Carlos Average
San Carlos Average
- ●USDA Zones 10a, averaged across San Carlos
- ●One soil character for all of San Carlos
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not San Carlos's 10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in San Carlos
Pull a site-specific report for your exact address in San Carlos, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that San Carlos averages can't show:
We read public map data around San Carlos — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the San Carlos average
How we know this about San Carlos
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals, with the labelled statewide window where none resolves; 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 city grain anywhere on this page — there is no city-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 Carlos
Is it too late to plant in San Carlos?
No — San Carlos has no 28°F killing freeze in the 30-year station record, so the growing season is year-round and there is no last-frost date to wait for. Planting is paced by rainfall, heat and daylength instead of by frost: start heat-lovers any month, and time cool-season crops (lettuce, brassicas, peas) for the cooler, wetter half of the year or for higher ground. Succession sowing every few weeks works all year, so the limit is what you can keep watered and harvested, not the calendar.
When does frost risk typically end in San Carlos?
It doesn't — San Carlos records no 28°F killing freeze at all across the 1991–2020 station record, so there is no spring frost date to plant after. Cold still matters with elevation: the higher you garden, the cooler the nights, and a few tropical crops sulk below about 60°F even where they never freeze.
How long is the growing season in San Carlos?
Year-round — the 1991–2020 station record for San Carlos contains no 28°F killing freeze, so there is no season to measure between freezes. What paces planting instead is heat, rainfall and daylength: the hottest, wettest stretch is the hard part for cool-season crops, not winter. Elevation is the one real exception — the higher you garden, the colder the nights get.
Is the soil safe to grow vegetables in San Carlos?
The federal record around San Carlos is a meaningful one — 3,863 documented sites, mostly Brownfields entries (3,498), the nearest Brownfields record under a tenth of a mile out — 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.
Everything above is measured at San Carlos's scale — its 10a band and its no killing freeze on record. Your yard writes its own version of San Carlos'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 Carlos’s own scale
7 of the readings below were taken at San Carlos's own scale — the 3,464 acres it covers and 3,863 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- San Carlos's own USDA hardiness band, zones 10aUSDA PHZM 2023
- No 28°F killing freeze in the 30-year station record covering San Carlos — a year-round growing seasonNOAA Regional Climate Centers ACIS, 1991-2020
- 3,863 documented contamination sites on the federal record near San Carlos, the closest Brownfields record under a tenth of a mile out from the town centreFederal environmental registers
- San Carlos's boundary and the 3,464 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear San Carlos's hardiness zoneGrowable Ground crop-matching engine
- San Carlos sits in the Central California Foothills and Coastal Mountains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of San Carloslydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so San Carlos's 3,464 acres read through its county's SSURGO summaryfrom San Mateo County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom San Mateo 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 San Mateo County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among San Carlos's 3,464 acreswhy one lot differs from the next →
- Which side of San Carlos you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,464 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 Carlos-wide figureread your own land →