Castroville, 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.
Expect okra, meyer lemon, california poppy, and artichoke to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Castroville, 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 Castroville 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 Castroville — soil, climate, flood, and parcel records. How we handle your address.
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Castroville — the short answer
Castroville, California: USDA zone 9b, about 317 days between hard freezes, across 653 acres of town.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 27
- Monterey County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 10
- Monterey County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~317
- Monterey County normal — NOAA 1991–2020, nearest to this town
- Town area
- 653 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 Monterey County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Castroville's average, not your lot's — a low corner or a tree line moves it. Against Castroville's 317-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Castroville
Each reading below is measured for Castroville itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsCastroville runs about 317 days between hard freezes (read from Monterey County, the closest normal to Castroville) — 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
MeasuredCastroville 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 Castroville is in
Castroville sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Castroville's own centroid rather than borrowed from Monterey County.
What Grows in Castroville
Every plant below cleared Castroville's own zone 9b and its 317-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Castroville?
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 27 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 10 — 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 Castroville
Closest first, within ~10 miles of Castroville. Listing isn't leaking, and distance isn't exposure.
- RBPG ENTERPRISES dba CASTROVILLE EXXONUnderground Storage Tanks · 1200 ft
- WESTERN PRECOOLING SYSTEMSBrownfields · 1300 ft
- CASTROVILLE 76Brownfields · 1600 ft
- CASTROVILLE 76 #256024Underground Storage Tanks · 1600 ft
- CASTROVILLE AUTO PARTSBrownfields · 1800 ft
- DBA ADVANCED TOWING QTY COLLISION AUTOBrownfields · 1900 ft
- CLINICA DE SALUD DEL VALLE DE SALINAS-CASTROVILLEBrownfields · 2000 ft
- GIRLS SCOUTS OF CALIFORNIA CENTRAL COASTBrownfields · 2000 ft
- PACIFIC BELLBrownfields · 2100 ft
- SEA MIST FARMSBrownfields · 2300 ft
- CASTROVILLE CHEVRON SERVICEUnderground Storage Tanks · 2300 ft
- GONZALEZ AUTO SERVICE AND SMOGBrownfields · 2300 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Castroville'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 Castroville.
Sources Checked
within ~10 miles of Castroville
Severity Distribution
within ~10 miles of Castroville
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Castroville, Brownfields runs higher than the national average — 981 sites within ~10 miles of Castroville. That's not a problem with your land — it's information about 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 Castroville
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 Castroville average
Your land is one point inside Castroville
Everything above resolves to Castroville as a whole — one PHZM band, read across 653 acres, with hard-freeze dates borrowed from Monterey 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 Castroville Average
Castroville Average
- ●USDA Zones 9b, averaged across Castroville
- ●One soil character for all of Castroville
- ●Frost dates read at Castroville's scale: Jan 27 to Dec 10
YOUR Parcel
- ✓Your exact zone, not Castroville's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Castroville
Pull a site-specific report for your exact address in Castroville, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Castroville averages can't show:
We read public map data around Castroville — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Castroville average
How we know this about Castroville
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 Monterey 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 Castroville
When does frost risk typically end in Castroville?
The last hard freeze (28°F) in Castroville typically lands around Jan 27, 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 17.
When is the first frost in Castroville?
The first hard freeze (28°F) in Castroville typically arrives around Dec 10, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 26, so the watching starts about Nov 10 — about 317 days after the spring freeze cleared.
How long is the growing season in Castroville?
Measured between 28°F hard freezes, Castroville sees about 317 frost-free days — roughly Jan 27 through Dec 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 17 to Nov 26, about 282 days.
Is the soil safe to grow vegetables in Castroville?
The federal record around Castroville is a meaningful one — 1,215 documented sites, mostly Brownfields entries (981), 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 Castroville?
From about Nov 10 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 10 (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 10. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Castroville's scale — its 9b band and its 317-day season. Your yard writes its own version of Castroville'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 Castroville’s own scale
5 of the readings below were taken at Castroville's own scale — the 653 acres it covers and 1,215 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Castroville's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 1,215 documented contamination sites on the federal record near Castroville, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Castroville's boundary and the 653 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~317-day seasonGrowable Ground crop-matching engine
- The ecoregion at Castroville'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 — Castroville has no normal of its own, so its county's is the closest measured readfrom Monterey County
- Soil character — no town-scale survey exists, so Castroville's 653 acres read through its county's SSURGO summaryfrom Monterey County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Monterey 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 Monterey County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Castroville's 653 acreswhy one lot differs from the next →
- Which side of Castroville you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 653 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 Castroville-wide figureread your own land →