Larkspur, California, sits in USDA hardiness zone 10a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Well-matched crops include okra, meyer lemon, california poppy, and artichoke, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Larkspur, 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 Larkspur 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 Larkspur — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Larkspur — the short answer
Larkspur, California: USDA zone 10a, about 336 days between hard freezes, across 2K acres of city.
- USDA zone
- 10a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 9
- Marin County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 11
- Marin County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~336
- Marin County normal — NOAA 1991–2020, nearest to this town
- City area
- 2K 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 Marin County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 10a is Larkspur's average, not your lot's — a low corner or a tree line moves it. Against Larkspur's 336-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Larkspur
Each reading below is measured for Larkspur itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsLarkspur runs about 336 days between hard freezes (read from Marin County, the closest normal to Larkspur) — 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
MeasuredLarkspur 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 Larkspur is in
Larkspur sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Larkspur's own centroid rather than borrowed from Marin County.
What Grows in Larkspur
Every plant below cleared Larkspur's own zone 10a and its 336-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Larkspur?
Almost never — the real question is what to plant next. 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 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 11 — 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.
Documented around Larkspur
Spotted lanternfly documented 21 miles from Larkspur, first recorded 2023. What to watch for.
What's on the federal record near Larkspur
Closest first, within ~10 miles of Larkspur. Listing isn't leaking, and distance isn't exposure.
- TAMALPAIS UNION HIGH SCHOOL DISTRICTBrownfields · 900 ft
- DAVID DEEBrownfields · 1300 ft
- 1000 S. ELISEO MED. BLDG., INC/VERNON WELDON, PRESIDENTBrownfields · 1400 ft
- T L HAND, MD, FACS OFFICE FACILITYBrownfields · 1400 ft
- Marin Gas & Auto ServiceUnderground Storage Tanks · 1500 ft
- MARIN GAS & AUTO SERVICESBrownfields · 1500 ft
- TEXACO SERVICE STATIONBrownfields · 1600 ft
- LARKSPUR CLEANERSBrownfields · 1600 ft
- UCSF-DEPT OF NEUROLOGICAL SURGERYBrownfields · 1700 ft
- SAVEMART SUPERMARKETS DBA LUCKY #720Brownfields · 1700 ft
- REDWOOD HIGH SCHOOLBrownfields · 1800 ft
- PRANDI PROPERTYBrownfields · 1800 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Larkspur'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 Larkspur.
Sources Checked
within ~10 miles of Larkspur
Severity Distribution
within ~10 miles of Larkspur
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Larkspur, Brownfields runs higher than the national average — 1,767 sites within ~10 miles of Larkspur. 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 Larkspur
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 Larkspur average
Your land is one point inside Larkspur
Everything above resolves to Larkspur as a whole — one PHZM band, read across 2K acres, with hard-freeze dates borrowed from Marin County’s record because no 30-year normal resolves at this city’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 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 Larkspur Average
Larkspur Average
- ●USDA Zones 10a, averaged across Larkspur
- ●One soil character for all of Larkspur
- ●Frost dates read at Larkspur's scale: Jan 9 to Dec 11
YOUR Parcel
- ✓Your exact zone, not Larkspur's 10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Larkspur
Pull a site-specific report for your exact address in Larkspur, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Larkspur averages can't show:
We read public map data around Larkspur — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Larkspur average
How we know this about Larkspur
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 at Marin 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 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 Larkspur
When does frost risk typically end in Larkspur?
The last hard freeze (28°F) in Larkspur typically lands around Jan 9, 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 Jan 30.
When is the first frost in Larkspur?
The first hard freeze (28°F) in Larkspur typically arrives around Dec 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 27, so the watching starts about Nov 11 — about 336 days after the spring freeze cleared.
How long is the growing season in Larkspur?
Measured between 28°F hard freezes, Larkspur sees about 336 frost-free days — roughly Jan 9 through Dec 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jan 30 to Nov 27, about 301 days.
Is the soil safe to grow vegetables in Larkspur?
The federal record around Larkspur is a meaningful one — 1,917 documented sites, mostly Brownfields entries (1,767), 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 Larkspur?
From about Nov 11 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 11 (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 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Larkspur's scale — its 10a band and its 336-day season. Your yard writes its own version of Larkspur'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 Larkspur’s own scale
6 of the readings below were taken at Larkspur's own scale — the 1,919 acres it covers and 1,917 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Larkspur's own USDA hardiness band, zones 10aUSDA PHZM 2023
- 1,917 documented contamination sites on the federal record near Larkspur, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- Larkspur's boundary and the 1,919 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 10a and a ~336-day seasonGrowable Ground crop-matching engine
- The ecoregion at Larkspur's own centroid, the Central California Foothills and Coastal MountainsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Larkspurlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The 28°F hard-freeze dates — Larkspur has no normal of its own, so its county's is the closest measured readfrom Marin County
- Soil character — no town-scale survey exists, so Larkspur's 1,919 acres read through its county's SSURGO summaryfrom Marin County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Marin 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 Marin County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Larkspur's 1,919 acreswhy one lot differs from the next →
- Which side of Larkspur you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,919 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 Larkspur-wide figureread your own land →
More in California
Growing region
Nearby growing guides