San Francisco County, in California, sits in USDA hardiness zone 10b — 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, meyer lemon, california poppy, and cabbage — though what thrives on any one site still turns on its specific soil, sun, and drainage.
San Francisco County lies within the San Francisco Bay Area — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring
San Francisco County holds more than one microclimate.
Soils and elevations shift across San Francisco County, so your frost dates and drainage aren't the county average. 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 Francisco County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
San Francisco County — the short answer
San Francisco County, California: USDA zone 10b, across 30K acres.
- 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
- County area
- 30K 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 San Francisco County's average, not your lot's — a low corner or a tree line moves it. Against that, see what your own ground reads.
Soil in San Francisco County
Across San Francisco County, the ground is predominantly Entisols, where Sirdrak, Candlestick, and Kron are the most extensive named soil series. The soil is generally well drained with a variable surface. Topsoil pH runs about 5.8, moderately acidic. Rainfall drains through hydrologic group D soils.
Soil order
Entisols
Drainage
Well drained
Hydric soils
0%
Soil still varies lot by lot — soil types explained.
How the ground varies across San Francisco County
The USDA soil survey maps 8% of San Francisco County as well drained — but another 5% drains differently: 5% somewhat excessively drained, 1% moderately well drained.
Sirdrak is the most extensive named soil at 19% of mapped acres, then Candlestick (4%) and Kron (2%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in San Francisco County
Each reading below is measured for San Francisco County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across San Francisco County are well drained, in hydrologic group D — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across San Francisco County runs about pH 5.8, on the acidic side.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Winter hardiness
MeasuredSan Francisco County 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 San Francisco County is in
San Francisco County sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. One consistent ecological setting across the whole county.
What Grows in San Francisco County
We scored all 1,086 plants against San Francisco County's own USDA zone 10b, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's California profile.
Documented around San Francisco County
- monarch butterfly75 documented records
Sighting records, so they follow observers as much as insects.
Safe to Grow Here?
What the federal record shows across San Francisco County — and how to grow with it.
We checked the federal record across San Francisco County — 4,577 documented sites across 7 of the 9 source types we track.
The most significant on record: 15 Superfund sites. 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 San Francisco 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.
What's on the federal record near San Francisco County
Closest first, across San Francisco County. Listing isn't leaking, and distance isn't exposure.
- BEACH CHALETBrownfields · 28.7 mi
- CCSF - DEPARTMENT OF THE ENVIRONMENTBrownfields · 28.7 mi
- 002S006W15P001MNitrate · 28.7 mi
- SAYEH PETROLIUM INC DBA LINCOL 76Brownfields · 28.7 mi
- Lincoln UnocalUnderground Storage Tanks · 28.7 mi
- MICHAEL SACK PAINTING INC/MS PAINTING COBrownfields · 28.7 mi
- ON TRACK CLEANERS GROUPBrownfields · 28.7 mi
- SOAP BOX CLEANERSBrownfields · 28.7 mi
- CCSF/PUC/WWE/WESTSIDE PUMP STATIONUnderground Storage Tanks · 28.8 mi
- SAFEWAY STORE #785Brownfields · 28.8 mi
- KEYME INCBrownfields · 28.8 mi
- 002S006W22Q001MNitrate · 28.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from San Francisco County'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 Francisco County.
Sources Checked
across San Francisco County
Severity Distribution
across San Francisco County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around San Francisco County, Brownfields runs higher than the national average — 4,228 sites across San Francisco County. 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.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in San Francisco County
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 Francisco County average
Your land is one point inside San Francisco County
Everything above resolves to San Francisco County as a whole — one PHZM band and one county frost record, read across 30K 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 county 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 county average.
Your Lot vs the San Francisco County Average
San Francisco County Average
- ●USDA Zones 10b, averaged across San Francisco County
- ●One soil character for all of San Francisco County
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not San Francisco County's 10b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in San Francisco County
Pull a site-specific report for your exact address in San Francisco County, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that San Francisco County averages can't show:
We read public map data around San Francisco County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the San Francisco County average
How we know this about San Francisco County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where San Francisco County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about San Francisco County
When does frost risk typically end in San Francisco County?
San Francisco County 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 San Francisco County?
The federal record around San Francisco County is a meaningful one — 4,577 documented sites, mostly Brownfields entries (4,228), the nearest Brownfields record about 29 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.
Everything above is measured at San Francisco County's scale — its 10b band and its zone 10b. Your yard writes its own version of San Francisco County's numbers: 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 California's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at San Francisco County’s own scale
7 of the readings below were taken at San Francisco County's own scale — the 3 most extensive soil series mapped here and 4,577 documented sites inside its boundary; 2 are borrowed from a wider read, named and linked below.
Measured here
- San Francisco County's own USDA hardiness band, zones 10bUSDA PHZM 2023
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in San Francisco CountyUSDA NRCS SSURGO
- 4,577 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Brownfields record about 29 miles outFederal environmental registers
- San Francisco County's boundary and the 29,878 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear San Francisco County's hardiness zoneGrowable Ground crop-matching engine
- San Francisco County sitting wholly inside the Central California Foothills and Coastal MountainsUS EPA Level III Ecoregions
- Open occurrence records documented in San Francisco County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
Inherited from a wider read
- The frost window — this county has no hard-freeze normal of its own, so the statewide dates stand infrom 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
- How the season shifts from one end of San Francisco County to the other — town normals split the differencetowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among San Francisco County's 29,878 acreswhy one lot differs from the next →
- Which of those 4,577 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over San Francisco Countyread your own land →