Stonyford, California, sits in USDA hardiness zone 9a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Expect tomato, artichoke, fig, and california poppy to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Stonyford, 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 Stonyford 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 Stonyford — soil, climate, flood, and parcel records. How we handle your address.
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Stonyford — the short answer
Stonyford, California: USDA zone 9a, about 329 days between hard freezes, across 899 acres of town.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 19
- Colusa County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 14
- Colusa County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~329
- Colusa County normal — NOAA 1991–2020, nearest to this town
- Town area
- 899 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 Colusa County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Stonyford's average, not your lot's — a low corner or a tree line moves it. Against Stonyford's 329-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Stonyford
Each reading below is measured for Stonyford itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsStonyford runs about 329 days between hard freezes (read from Colusa County, the closest normal to Stonyford) — 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
MeasuredStonyford 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 Stonyford is in
Stonyford sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Stonyford's own centroid, and it is not what its county reads: Colusa County is mostly Central California Valley. The wider page above you is answering a different question about different ground.
What Grows in Stonyford
Plants matched to Stonyford's USDA zones 9a, ordered by how much hardiness margin each has here — the ones with room to spare at both ends of this town's band lead. Each links to its full growing profile.
Is it too late to plant in Stonyford?
Rarely: the season closes in stages, not all at once, and each stage has its crops. 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 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 14 — 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 Stonyford
Closest first, within ~10 miles of Stonyford. Listing isn't leaking, and distance isn't exposure.
- PACIFIC BELLBrownfields · 2600 ft
- LOUISIANA-PACIFIC CORPBrownfields · 0.9 mi
- 018N006W29L001MNitrate · 1.2 mi
- UnknownMining · 1.7 mi
- Unnamed LocationMining · 1.7 mi
- LionMining · 2.7 mi
- Teathers ProspectMining · 2.8 mi
- Liberty Chrome MineMining · 2.8 mi
- Chrome Wonder DepositMining · 2.8 mi
- St. JohnMining · 3.3 mi
- MONTGOMERY CREEK PRESERVEBrownfields · 3.7 mi
- Unnamed ProspectMining · 4.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Stonyford'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 Stonyford.
Severity Distribution
within ~10 miles of Stonyford
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Stonyford, Mining runs higher than the national average — 32 sites within ~10 miles of Stonyford. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Stonyford
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 Stonyford average
Your land is one point inside Stonyford
Everything above resolves to Stonyford as a whole — one PHZM band, read across 899 acres, with hard-freeze dates borrowed from Colusa 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 Stonyford Average
Stonyford Average
- ●USDA Zones 9a, averaged across Stonyford
- ●One soil character for all of Stonyford
- ●Frost dates read at Stonyford's scale: Jan 19 to Dec 14
YOUR Parcel
- ✓Your exact zone, not Stonyford's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Stonyford
Pull a site-specific report for your exact address in Stonyford, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Stonyford averages can't show:
We read public map data around Stonyford — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Stonyford average
How we know this about Stonyford
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 Colusa 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 Stonyford
When does frost risk typically end in Stonyford?
The last hard freeze (28°F) in Stonyford typically lands around Jan 19, 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 9.
When is the first frost in Stonyford?
The first hard freeze (28°F) in Stonyford typically arrives around Dec 14, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 30, so the watching starts about Nov 14 — about 329 days after the spring freeze cleared.
How long is the growing season in Stonyford?
Measured between 28°F hard freezes, Stonyford sees about 329 frost-free days — roughly Jan 19 through Dec 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 9 to Nov 30, about 294 days.
Is the soil safe to grow vegetables in Stonyford?
The federal record around Stonyford shows 40 documented sites, mostly Mining entries (32), the nearest Brownfields record about 0.5 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Stonyford?
From about Nov 14 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 14 (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 14. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Stonyford's scale — its 9a band and its 329-day season. Your yard writes its own version of Stonyford'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 Stonyford’s own scale
4 of the readings below were taken at Stonyford's own scale — the 899 acres it covers and 40 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- Stonyford's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 40 documented contamination sites on the federal record near Stonyford, the closest Brownfields record about 0.5 miles out from the town centreFederal environmental registers
- Stonyford's boundary and the 899 acres inside itUS Census TIGER/Line 2025
- Stonyford 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 — Stonyford has no normal of its own, so its county's is the closest measured readfrom Colusa County
- Soil character — no town-scale survey exists, so Stonyford's 899 acres read through its county's SSURGO summaryfrom Colusa County
- The candidate plant list — California's curated set, filtered to this zone band and re-ordered by how much margin each has herefrom California
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Colusa 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 Colusa County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Stonyford's 899 acreswhy one lot differs from the next →
- Which side of Stonyford you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 899 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.5 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 Stonyford-wide figureread your own land →