Redwood Valley, California, sits in USDA hardiness zone 9a — a zone band wide enough that plant choice, not possibility, is the interesting question.
On paper, artichoke, fig, california poppy, and cabbage all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Redwood Valley, 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 Redwood Valley 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 Redwood Valley — soil, climate, flood, and parcel records. How we handle your address.
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Redwood Valley — the short answer
Redwood Valley, California: USDA zone 9a, about 304 days between hard freezes, across 2K acres of town.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 5
- Mendocino County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 6
- Mendocino County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~304
- Mendocino County normal — NOAA 1991–2020, nearest to this town
- Town 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 Mendocino County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Redwood Valley's average, not your lot's — a low corner or a tree line moves it. Against Redwood Valley's 304-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Redwood Valley
Each reading below is measured for Redwood Valley itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsRedwood Valley runs about 304 days between hard freezes (read from Mendocino County, the closest normal to Redwood Valley) — 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
MeasuredRedwood Valley 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 Redwood Valley is in
Redwood Valley sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Redwood Valley's own centroid, and it is not what its county reads: Mendocino County is mostly Klamath Mountains/California High North Coast Range. The wider page above you is answering a different question about different ground.
What Grows in Redwood Valley
Every plant below cleared Redwood Valley's own zone 9a and its 304-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Redwood Valley?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Jan 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 6 — 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 Redwood Valley
Closest first, within ~10 miles of Redwood Valley. Listing isn't leaking, and distance isn't exposure.
- Redwood Valley Gas StationUnderground Storage Tanks · 850 ft
- T & T PAVING INC DBA VALLEY PAVINGBrownfields · 0.6 mi
- JOHNSON FAMILY RANCH, INCBrownfields · 0.9 mi
- CERRO PACIFIC LUMBER INCBrownfields · 1.0 mi
- NORTH AMERICAN ORGANICSBrownfields · 1.2 mi
- CALTRANS CONSTRUCTIONBrownfields · 1.3 mi
- 017N012W33G001MNitrate · 1.4 mi
- FERRANTI CONSTRUCTION INCBrownfields · 1.4 mi
- 016N012W07A001MNitrate · 1.4 mi
- 016N012W16C001MNitrate · 1.5 mi
- REDWOOD VALLEY COUNTY WATER DISTRICTBrownfields · 1.5 mi
- TED E SCHNEIDERBrownfields · 1.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Redwood Valley'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 Redwood Valley.
Total Sites
309
within ~10 miles of Redwood Valley
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Redwood Valley
Severity Distribution
within ~10 miles of Redwood Valley
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Redwood Valley, two things run higher than the national average within ~10 miles of Redwood Valley — Brownfields (254 sites) and PFAS (4 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Redwood Valley
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 Redwood Valley average
Your land is one point inside Redwood Valley
Everything above resolves to Redwood Valley as a whole — one PHZM band, read across 2K acres, with hard-freeze dates borrowed from Mendocino County’s record because no 30-year normal resolves at this town’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 town 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 Redwood Valley Average
Redwood Valley Average
- ●USDA Zones 9a, averaged across Redwood Valley
- ●One soil character for all of Redwood Valley
- ●Frost dates read at Redwood Valley's scale: Feb 5 to Dec 6
YOUR Parcel
- ✓Your exact zone, not Redwood Valley's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Redwood Valley
Pull a site-specific report for your exact address in Redwood Valley, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Redwood Valley averages can't show:
We read public map data around Redwood Valley — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Redwood Valley average
How we know this about Redwood Valley
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Mendocino 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 town grain anywhere on this page — there is no town-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 Redwood Valley
When does frost risk typically end in Redwood Valley?
The last hard freeze (28°F) in Redwood Valley typically lands around Feb 5, 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 26.
When is the first frost in Redwood Valley?
The first hard freeze (28°F) in Redwood Valley typically arrives around Dec 6, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 22, so the watching starts about Nov 6 — about 304 days after the spring freeze cleared.
How long is the growing season in Redwood Valley?
Measured between 28°F hard freezes, Redwood Valley sees about 304 frost-free days — roughly Feb 5 through Dec 6, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 26 to Nov 22, about 269 days.
Is the soil safe to grow vegetables in Redwood Valley?
The federal record around Redwood Valley is a meaningful one — 309 documented sites, mostly Brownfields entries (254), the nearest Underground Storage Tanks 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 Redwood Valley?
From about Nov 6 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 6 (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 6. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Redwood Valley's scale — its 9a band and its 304-day season. Your yard writes its own version of Redwood Valley'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 Redwood Valley’s own scale
5 of the readings below were taken at Redwood Valley's own scale — the 1,757 acres it covers and 309 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Redwood Valley's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 309 documented contamination sites on the federal record near Redwood Valley, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Redwood Valley's boundary and the 1,757 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~304-day seasonGrowable Ground crop-matching engine
- Redwood Valley sits in the Central California Foothills and Coastal Mountains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Redwood Valley has no normal of its own, so its county's is the closest measured readfrom Mendocino County
- Soil character — no town-scale survey exists, so Redwood Valley's 1,757 acres read through its county's SSURGO summaryfrom Mendocino County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Mendocino 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 Mendocino County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Redwood Valley's 1,757 acreswhy one lot differs from the next →
- Which side of Redwood Valley you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,757 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Redwood Valley-wide figureread your own land →