South San Francisco, California, sits in USDA hardiness zone 10b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Growers here do well with artichoke, meyer lemon, california poppy, and cabbage — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in South San Francisco, 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 South San Francisco 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 South San Francisco — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
South San Francisco — the short answer
South San Francisco, California: USDA zone 10b, across 6K acres of city.
- USDA zone
- 10b
- USDA PHZM 2023
- Last hard freeze (statewide)
- Jan 19 - Mar 19
- NOAA RCC ACIS 1991–2020, state middle half
- First hard freeze (statewide)
- Nov 29 - Dec 12
- NOAA RCC ACIS 1991–2020, state middle half
- City area
- 6K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Where no local normal resolves, the figure is the statewide middle-half window, labelled as such rather than passed off as local.
Hardiness Zone Range
Growing Season
Zone 10b is South San Francisco's average, not your lot's — a low corner or a tree line moves it. Against that, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in South San Francisco
Each reading below is measured for South San Francisco itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Winter hardiness
MeasuredSouth San Francisco sits in USDA hardiness zone 10b.
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 South San Francisco is in
South San Francisco sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at South San Francisco's own centroid rather than borrowed from its county.
What Grows in South San Francisco
Every plant below cleared South San Francisco's own zone 10b. Each card opens that plant's California profile. How we score.
Documented around South San Francisco
Spotted lanternfly documented 10 miles from South San Francisco, first recorded 2023. What to watch for.
What's on the federal record near South San Francisco
Closest first, within ~10 miles of South San Francisco. Listing isn't leaking, and distance isn't exposure.
- ONSITE DENTAL LLCBrownfields · 900 ft
- GENENTECH INC - LOWER CAMPUSToxics Release Inventory · 900 ft
- GENENTECH INC - LOWER CAMPUSBrownfields · 900 ft
- LITHOTYPE COMPANYBrownfields · 1000 ft
- LITHOTYPE COMPANYToxics Release Inventory · 1000 ft
- GENENTECH INC - B35/38Brownfields · 1000 ft
- GENENTECH INC FOUNDERS RESEARCH CENTER (MID CAMPUS)Brownfields · 1200 ft
- MARINE MAGNESIUM CO, MARINE MAGNESIUM PLANTBrownfields · 1500 ft
- MARINE MAGNESIUM CO, MARINE MAGNESIUM PLANTToxics Release Inventory · 1500 ft
- KORET OF CALIFORNIABrownfields · 1800 ft
- GENENTECH INC - UPPER CAMPUS NORTHBrownfields · 1900 ft
- GENENTECH INC - UPPER CAMPUS SOUTHBrownfields · 2100 ft
6 more sites are on the record inside the same radius.
Measured from South San Francisco'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 South San Francisco.
Total Sites
7,388
within ~10 miles of South San Francisco
Risk Level
Elevated
Highest-severity
16 Superfund sites
Sources Checked
within ~10 miles of South San Francisco
Severity Distribution
within ~10 miles of South San Francisco
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around South San Francisco, Brownfields runs higher than the national average — 6,842 sites within ~10 miles of South San Francisco. That's not a problem with your land — it's information about it.
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 South San Francisco
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 South San Francisco average
Your land is one point inside South San Francisco
Everything above resolves to South San Francisco as a whole — one PHZM band and one 28°F frost record, read across 6K 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 South San Francisco Average
South San Francisco Average
- ●USDA Zones 10b, averaged across South San Francisco
- ●One soil character for all of South San Francisco
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not South San Francisco's 10b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in South San Francisco
Pull a site-specific report for your exact address in South San Francisco, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that South San Francisco averages can't show:
We read public map data around South San Francisco — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the South San Francisco average
How we know this about South San Francisco
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 South San Francisco
When does frost risk typically end in South San Francisco?
South San Francisco has no hard-freeze normal of its own, so it follows California's statewide window: the middle half of counties see their last spring hard freeze (28°F) around Jan 19 - Mar 19 and their first fall hard freeze around Nov 29 - Dec 12, per NOAA Regional Climate Centers ACIS (1991–2020). Frost dates shift with elevation and local microclimate, so watch your own site's cold pockets. 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.
Is the soil safe to grow vegetables in South San Francisco?
The federal record around South San Francisco is a meaningful one — 7,388 documented sites, mostly Brownfields entries (6,842), the nearest Brownfields record about 0.2 miles 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.
How do I protect my plants from frost in South San Francisco?
As the season closes around California's statewide first fall hard freeze (28°F) near Nov 29 - Dec 12 (NOAA Regional Climate Centers ACIS (1991–2020)), 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 the first hard night. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at South San Francisco's scale — its 10b band and its zone 10b. Your yard writes its own version of South San Francisco'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 South San Francisco’s own scale
6 of the readings below were taken at South San Francisco's own scale — the 5,891 acres it covers and 7,388 documented sites around it; 3 are borrowed from a wider read, named and linked below.
Measured here
- South San Francisco's own USDA hardiness band, zones 10bUSDA PHZM 2023
- 7,388 documented contamination sites on the federal record near South San Francisco, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- South San Francisco's boundary and the 5,891 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear South San Francisco's hardiness zoneGrowable Ground crop-matching engine
- The ecoregion at South San Francisco's own centroid, the Central California Foothills and Coastal MountainsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of South San Franciscolydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The frost window — no local hard-freeze normal resolved here, so the statewide dates stand infrom California
- Soil character — no town-scale survey exists, so South San Francisco's 5,891 acres read through the state summaryfrom California
- The growing challenges every California grower plans around — written at state scale, so they stay on the state guidefrom California
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among South San Francisco's 5,891 acreswhy one lot differs from the next →
- Which side of South San Francisco you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 5,891 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.2 miles 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 South San Francisco-wide figureread your own land →
More in California
Wider growing context
What grows across CaliforniaSouth San Francisco sits outside our named growing regions, so California as a whole is its closest context here.
Nearby growing guides