Hornitos, California, sits in USDA hardiness zone 9b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Reliable performers under these conditions include tomato, artichoke, fig, and california poppy; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Hornitos, 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 Hornitos 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 Hornitos — soil, climate, flood, and parcel records. How we handle your address.
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Hornitos — the short answer
Hornitos, California: USDA zone 9b, about 249 days between hard freezes, across 739 acres of town.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 20
- Mariposa County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Nov 24
- Mariposa County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~249
- Mariposa County normal — NOAA 1991–2020, nearest to this town
- Town area
- 739 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 Mariposa County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Hornitos's average, not your lot's — a low corner or a tree line moves it. Against Hornitos's 249-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Hornitos
Each reading below is measured for Hornitos itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsHornitos runs about 249 days between hard freezes (read from Mariposa County, the closest normal to Hornitos) — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredHornitos sits in USDA hardiness zone 9b.
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 Hornitos is in
Hornitos sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Hornitos's own centroid, and it is not what its county reads: Mariposa County is mostly Sierra Nevada. The wider page above you is answering a different question about different ground.
What Grows in Hornitos
Plants matched to Hornitos's USDA zones 9b, 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 Hornitos?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 20 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 24 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
What's on the federal record near Hornitos
Closest first, within ~10 miles of Hornitos. Listing isn't leaking, and distance isn't exposure.
- Washington MineMining · 1.8 mi
- WashingtonMining · 1.8 mi
- AndersonMining · 1.8 mi
- White QuartzMining · 2.1 mi
- DossMining · 2.2 mi
- Blue MoonMining · 3.6 mi
- BadgerMining · 3.6 mi
- American EagleMining · 4.0 mi
- American EaglesMining · 4.1 mi
- Silver LeadMining · 4.1 mi
- LAKE MCSWAIN RECREATION AREABrownfields · 4.2 mi
- Mount Gaines MineMining · 4.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Hornitos'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 Hornitos.
Sources Checked
within ~10 miles of Hornitos
Severity Distribution
within ~10 miles of Hornitos
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Hornitos, Mining runs higher than the national average — 47 sites within ~10 miles of Hornitos. 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 Hornitos
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 Hornitos average
Your land is one point inside Hornitos
Everything above resolves to Hornitos as a whole — one PHZM band, read across 739 acres, with hard-freeze dates borrowed from Mariposa 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 Hornitos Average
Hornitos Average
- ●USDA Zones 9b, averaged across Hornitos
- ●One soil character for all of Hornitos
- ●Frost dates read at Hornitos's scale: Mar 20 to Nov 24
YOUR Parcel
- ✓Your exact zone, not Hornitos's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Hornitos
Pull a site-specific report for your exact address in Hornitos, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Hornitos averages can't show:
We read public map data around Hornitos — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Hornitos average
How we know this about Hornitos
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 Mariposa 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 Hornitos
When does frost risk typically end in Hornitos?
The last hard freeze (28°F) in Hornitos typically lands around Mar 20, 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 Apr 10.
When is the first frost in Hornitos?
The first hard freeze (28°F) in Hornitos typically arrives around Nov 24, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 10, so the watching starts about Oct 25 — about 249 days after the spring freeze cleared.
How long is the growing season in Hornitos?
Measured between 28°F hard freezes, Hornitos sees about 249 frost-free days — roughly Mar 20 through Nov 24, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 10 to Nov 10, about 214 days.
Is the soil safe to grow vegetables in Hornitos?
The federal record around Hornitos runs heavier than most — 66 documented sites, mostly Mining entries (47), the nearest Mining record about 1.8 miles 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 Hornitos?
From about Oct 25 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 Nov 24 (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 Nov 24. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Hornitos's scale — its 9b band and its 249-day season. Your yard writes its own version of Hornitos'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 Hornitos’s own scale
4 of the readings below were taken at Hornitos's own scale — the 739 acres it covers and 66 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- Hornitos's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 66 documented contamination sites on the federal record near Hornitos, the closest Mining record about 1.8 miles out from the town centreFederal environmental registers
- Hornitos's boundary and the 739 acres inside itUS Census TIGER/Line 2025
- Hornitos 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 — Hornitos has no normal of its own, so its county's is the closest measured readfrom Mariposa County
- Soil character — no town-scale survey exists, so Hornitos's 739 acres read through its county's SSURGO summaryfrom Mariposa 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 Mariposa 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 Mariposa County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Hornitos's 739 acreswhy one lot differs from the next →
- Which side of Hornitos you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 739 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Mining record about 1.8 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 Hornitos-wide figureread your own land →