Rohnert Park, California, sits in USDA hardiness zone 9a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Well-matched crops include artichoke, fig, california poppy, and cabbage, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Rohnert Park, 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 Rohnert Park 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 Rohnert Park — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Rohnert Park — the short answer
Rohnert Park, California: USDA zone 9a, about 323 days between hard freezes, across 5K 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
- 5K 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 Rohnert Park's average, not your lot's — a low corner or a tree line moves it. Against Rohnert Park's 323-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Rohnert Park
Each reading below is measured for Rohnert Park itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsRohnert Park runs about 323 days between hard freezes (read from Sonoma County, the closest normal to Rohnert Park) — 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
MeasuredRohnert Park 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 Rohnert Park is in
Rohnert Park sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Rohnert Park's own centroid rather than borrowed from Sonoma County.
What Grows in Rohnert Park
Every plant below cleared Rohnert Park'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 Rohnert Park?
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 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. With almost year-round growing weather, timing is about heat and rainfall more than frost — some bench is always in play.
What's on the federal record near Rohnert Park
Closest first, within ~10 miles of Rohnert Park. Listing isn't leaking, and distance isn't exposure.
- ROHNERT PARK CITY OFBrownfields · 1000 ft
- RALEYS 377Brownfields · 1300 ft
- MAJOR CLEANERSBrownfields · 1300 ft
- TOWNE CLEANERSBrownfields · 1400 ft
- ROSS DRESS FOR LESS #0008Brownfields · 1500 ft
- O'REILLY AUTO PARTS #2575Brownfields · 1600 ft
- THE COMMONS APARTMENTSBrownfields · 1900 ft
- AT&TBrownfields · 2100 ft
- NEW CINGULAR WIRELESS PCS LLCBrownfields · 2100 ft
- CALIFORNIA UNITED MECHANICAL INC DBA UMIBrownfields · 2100 ft
- Graton Resort and CasinoPFAS · 2200 ft
- SONOMA STATE UNIVERSITYPFAS · 2200 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Rohnert Park'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 Rohnert Park.
Total Sites
2,129
within ~10 miles of Rohnert Park
Risk Level
Elevated
Highest-severity
11 Superfund sites
Sources Checked
within ~10 miles of Rohnert Park
Severity Distribution
within ~10 miles of Rohnert Park
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Rohnert Park, Brownfields runs higher than the national average — 1,884 sites within ~10 miles of Rohnert Park. 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 Rohnert Park
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 Rohnert Park average
Your land is one point inside Rohnert Park
Everything above resolves to Rohnert Park as a whole — one PHZM band, read across 5K 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 Rohnert Park Average
Rohnert Park Average
- ●USDA Zones 9a, averaged across Rohnert Park
- ●One soil character for all of Rohnert Park
- ●Frost dates read at Rohnert Park's scale: Jan 23 to Dec 12
YOUR Parcel
- ✓Your exact zone, not Rohnert Park's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Rohnert Park
Pull a site-specific report for your exact address in Rohnert Park, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Rohnert Park averages can't show:
We read public map data around Rohnert Park — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Rohnert Park average
How we know this about Rohnert Park
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 Rohnert Park
When does frost risk typically end in Rohnert Park?
The last hard freeze (28°F) in Rohnert Park 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 Rohnert Park?
The first hard freeze (28°F) in Rohnert Park 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 Rohnert Park?
Measured between 28°F hard freezes, Rohnert Park 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 Rohnert Park?
The federal record around Rohnert Park is a meaningful one — 2,129 documented sites, mostly Brownfields entries (1,884), 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 Rohnert Park?
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 Rohnert Park's scale — its 9a band and its 323-day season. Your yard writes its own version of Rohnert Park'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 Rohnert Park’s own scale
5 of the readings below were taken at Rohnert Park's own scale — the 4,663 acres it covers and 2,129 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Rohnert Park's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 2,129 documented contamination sites on the federal record near Rohnert Park, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- Rohnert Park's boundary and the 4,663 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 Rohnert Park'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 — Rohnert Park 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 Rohnert Park's 4,663 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 Rohnert Park's 4,663 acreswhy one lot differs from the next →
- Which side of Rohnert Park you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,663 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 Rohnert Park-wide figureread your own land →
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