The Mendocino / Anderson Valley spans USDA hardiness zone 9a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Anchored in Mendocino County, California — the single county that wholly contains both the Anderson Valley AVA (27 CFR §9.100) and the broader Mendocino AVA (27 CFR §9.98) — this coastal-influenced Northern California region runs a long USDA zone 9a growing season of roughly 304 frost-free days. These conditions suit tomato, artichoke, fig, and california poppy — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
The Mendocino / Anderson Valley spans California.
Your yard isn't all of the Mendocino / Anderson Valley.
The Mendocino / Anderson Valley spans USDA zones 9a, but your parcel sits in exactly one — and slope, tree cover, and low spots nudge it further. 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 Mendocino / Anderson Valley — soil, climate, flood, and parcel records. How we handle your address.
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The Mendocino / Anderson Valley — the short answer
The Mendocino / Anderson Valley: USDA zones 9a, 304 frost-free days, in California.
- USDA zones
- 9a
- USDA PHZM 2023, aggregated over the footprint
- Frost-free season
- 304 days
- NOAA Regional Climate Centers ACIS, 1991–2020
- Counties
- 1
- US Census TIGER/Line 2025
- Region type
- County cluster
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. Where a region publishes no measured season, no season figure is shown.
Hardiness Zone Range
What Grows in the Mendocino / Anderson Valley
Plants matched to the Mendocino / Anderson Valley's USDA zones 9a, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of the Mendocino / Anderson Valley
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets the Mendocino / Anderson Valley’s USDA zones 9a — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground across the Mendocino / Anderson Valley
The USDA soil survey maps this ground county by county. These are those records weighted by land area across one member county — this region’s own profile, not a state figure.
The ground is predominantly Alfisols, at 52% of mapped acres, followed by Inceptisols (21%), Mollisols (19%) and Entisols (5%). Seven soil orders appear somewhere inside the footprint, which is the honest reason a regional soil answer only goes so far. The most extensive named soils are Ornbaun, Hopland, and Yorkville.
78% of those acres are well drained, and another 9% somewhat excessively drained, 5% moderately well drained. Topsoil pH runs 5.8–6.3 in that county’s own record.
Soil order
Alfisols
Drainage
Well drained
Topsoil pH
5.8–6.3
Hydric soils
2%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Mendocino / Anderson Valley
The soil survey reads this ground county by county, and the readings above are those records summed across the Mendocino / Anderson Valley. Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records78% of the mapped acres across the Mendocino / Anderson Valley are well drained — ground that drains quickly. That is area-weighted across its one mapped county.
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
From county recordsTopsoil across the Mendocino / Anderson Valley runs pH 5.8–6.3 — near neutral in the one record covering it.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Safe to Grow Here?
What the federal record shows across the Mendocino / Anderson Valley — and how to grow with it.
Across the Mendocino / Anderson Valley's 1 county the federal record holds 787 documented sites, mostly Brownfields (568), Nitrate (80) and Underground Storage Tanks (60). The heaviest single county is Mendocino County, with 787.
That is a regional count, not a reading of any one lot — proximity to a documented site is information, not a diagnosis. Open the map outlined to the Mendocino / Anderson Valley to see which records sit where you actually grow.
Sources Checked
Summed across the county in the Mendocino / Anderson Valley
A note from Gnorman
What an experienced grower watches for around here
In and around the Mendocino / Anderson Valley, two things run higher than the national average across the county in the Mendocino / Anderson Valley — Brownfields (568 sites) and Mining (52 sites). 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.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside the Mendocino / Anderson Valley
Everything above resolves to the Mendocino / Anderson Valley as a whole — a footprint spanning USDA zones 9a. Your parcel sits in exactly one of them. 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 region 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 regional average.
Your Lot vs the Mendocino / Anderson Valley Average
Mendocino / Anderson Valley Average
- ●USDA Zones 9a, averaged across Mendocino / Anderson Valley
- ●One soil character for all of Mendocino / Anderson Valley
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Mendocino / Anderson Valley's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Mendocino / Anderson Valley
Pull a site-specific report for your exact address in the Mendocino / Anderson Valley — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Mendocino / Anderson Valley averages can't show:
We read public map data around The Mendocino / Anderson Valley — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mendocino / Anderson Valley average
How we know this about the Mendocino / Anderson Valley
The boundary: a cluster of neighboring counties. Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the counties inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about the Mendocino / Anderson Valley
What hardiness zone is the Mendocino / Anderson Valley?
The Mendocino / Anderson Valley spans USDA hardiness zones 9a, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's counties. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
What grows well in the Mendocino / Anderson Valley?
The Mendocino / Anderson Valley's conditions suit plants such as Tomato, Artichoke, Fig, California Poppy, Rosemary, Olive. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is the Mendocino / Anderson Valley defined?
The Mendocino / Anderson Valley is defined here as a curated cluster of 1 neighboring counties that share a growing character. Growing regions have no official boundary, so this footprint is our published one — every county in it is named on this page.
Which states does the Mendocino / Anderson Valley cover?
The Mendocino / Anderson Valley spans California. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Pacific Northwest, California Central Valley, Sacramento Valley, San Joaquin Valley, Sierra Nevada Foothills, and Sonoran Desert share at least one state with the Mendocino / Anderson Valley. Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at the Mendocino / Anderson Valley’s own scale
5 of the readings below were taken at the Mendocino / Anderson Valley's own scale — the zone 9a band across its footprint and 787 documented federal contamination records across its one county, 787 of them in Mendocino County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 9a aggregated across the footprint's one countyUSDA PHZM 2023
- The boundary itself — the 1 county this region is curated fromGrowable Ground subregion registry
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The federal contamination record over the whole footprint — 787 documented federal contamination records across its one county, 787 of them in Mendocino County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 52% Alfisols, topsoil pH 5.8–6.3, area-weighted across its one mapped countyUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 9afrom California
What this page can’t tell you
- Frost dates — they swing too far across a footprint this size to quote as one regional numberfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore the Mendocino / Anderson Valley
State growing guides
Counties in this region
Other growing regions across California
The maritime Northwest west of the Cascade crest — mild, wet winters and dry summers behind berries, tree fruit, and lush cool-season gardens. (Union of the west-side ecoregions.)
A vast flat alluvial trough with hot dry summers and rich soils — one of the most productive agricultural regions on earth, from almonds and stone fruit to row crops.
The cooler, wetter northern half of the Central Valley — rice, walnuts, tomatoes, and orchard fruit on rich alluvial bottomland.
The hot southern half of California's Central Valley — deep soils and intense sun behind almonds, stone fruit, grapes, and row crops at vast scale.
California's Gold Country foothills — rocky, well-drained slopes and warm days that suit wine grapes, olives, and Mediterranean orchard crops.
A warm desert of saguaro and palo verde with mild winters that allow desert citrus, dates, and prickly pear alongside intensive irrigated gardening.