Petaluma, California, sits in USDA hardiness zone 9a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Growers here do well with artichoke, fig, california poppy, and cabbage — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Petaluma, 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 Petaluma 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 Petaluma — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Petaluma — the short answer
Petaluma, California: USDA zone 9a, about 323 days between hard freezes, across 9K acres of city.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 23
- Sonoma County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 12
- Sonoma County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~323
- Sonoma County normal — NOAA 1991–2020, nearest to this town
- City area
- 9K 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 Sonoma County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Petaluma's average, not your lot's — a low corner or a tree line moves it. Against Petaluma's 323-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Petaluma
Each reading below is measured for Petaluma itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsPetaluma runs about 323 days between hard freezes (read from Sonoma County, the closest normal to Petaluma) — 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
MeasuredPetaluma 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 Petaluma is in
Petaluma sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Petaluma's own centroid rather than borrowed from Sonoma County.
What Grows in Petaluma
Every plant below cleared Petaluma's own zone 9a and its 323-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Petaluma?
Usually not — gardeners here simply switch what goes in the ground as the season moves. 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 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 12 — long-season crops need about 90 days of runway, quick greens only 30. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
What's on the federal record near Petaluma
Closest first, within ~10 miles of Petaluma. Listing isn't leaking, and distance isn't exposure.
- SONOMA COUNTY WASTE MANAGEMENT AGENCYBrownfields · 500 ft
- 4TH DISTRICT AGRICULTURAL ASSOCIATION - SONOMA MARIN FAIRBrownfields · 600 ft
- SPROUTS FARMERS MARKETS #274Brownfields · 700 ft
- CVS PHARMACY #17586Brownfields · 700 ft
- DICKS SPORTING GOODS #1048Brownfields · 700 ft
- ULTA BEAUTY 606Brownfields · 700 ft
- TJ MAXX 1176Brownfields · 700 ft
- TARGET STORE T2601Brownfields · 700 ft
- PETSMART #2532Brownfields · 950 ft
- SHERWIN-WILLIAMS 8683Brownfields · 1000 ft
- SHELL SERVICE STATIONBrownfields · 1000 ft
- SALONCENTRIC 5942Brownfields · 1100 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Petaluma'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 Petaluma.
Sources Checked
within ~10 miles of Petaluma
Severity Distribution
within ~10 miles of Petaluma
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Petaluma, Brownfields runs higher than the national average — 962 sites within ~10 miles of Petaluma. 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 Petaluma
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 Petaluma average
Your land is one point inside Petaluma
Everything above resolves to Petaluma as a whole — one PHZM band, read across 9K acres, with hard-freeze dates borrowed from Sonoma 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 Petaluma Average
Petaluma Average
- ●USDA Zones 9a, averaged across Petaluma
- ●One soil character for all of Petaluma
- ●Frost dates read at Petaluma's scale: Jan 23 to Dec 12
YOUR Parcel
- ✓Your exact zone, not Petaluma's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Petaluma
Pull a site-specific report for your exact address in Petaluma, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Petaluma averages can't show:
We read public map data around Petaluma — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Petaluma average
How we know this about Petaluma
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 Sonoma 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 Petaluma
When does frost risk typically end in Petaluma?
The last hard freeze (28°F) in Petaluma typically lands around Jan 23, 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 13.
When is the first frost in Petaluma?
The first hard freeze (28°F) in Petaluma typically arrives around Dec 12, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 28, so the watching starts about Nov 12 — about 323 days after the spring freeze cleared.
How long is the growing season in Petaluma?
Measured between 28°F hard freezes, Petaluma sees about 323 frost-free days — roughly Jan 23 through Dec 12, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 13 to Nov 28, about 288 days.
Is the soil safe to grow vegetables in Petaluma?
The federal record around Petaluma runs heavier than most — 1,146 documented sites, mostly Brownfields entries (962), the nearest Brownfields record under a tenth of a mile out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Petaluma?
From about Nov 12 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 12 (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 12. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Petaluma's scale — its 9a band and its 323-day season. Your yard writes its own version of Petaluma'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 Petaluma’s own scale
5 of the readings below were taken at Petaluma's own scale — the 9,226 acres it covers and 1,146 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Petaluma's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 1,146 documented contamination sites on the federal record near Petaluma, the closest Brownfields record under a tenth of a mile out from the town centreFederal environmental registers
- Petaluma's boundary and the 9,226 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~323-day seasonGrowable Ground crop-matching engine
- The ecoregion at Petaluma'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 — Petaluma has no normal of its own, so its county's is the closest measured readfrom Sonoma County
- Soil character — no town-scale survey exists, so Petaluma's 9,226 acres read through its county's SSURGO summaryfrom Sonoma County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Sonoma 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 Sonoma County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Petaluma's 9,226 acreswhy one lot differs from the next →
- Which side of Petaluma you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 9,226 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 Petaluma-wide figureread your own land →
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