Casa de Oro-Mount Helix, California, sits in USDA hardiness zone 10b — a zone band wide enough that plant choice, not possibility, is the interesting question.
These conditions suit avocado, meyer lemon, tomato, and artichoke — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Casa de Oro-Mount Helix, 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 Casa de Oro-Mount Helix 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 Casa de Oro-Mount Helix — soil, climate, flood, and parcel records. How we handle your address.
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Casa de Oro-Mount Helix — the short answer
Casa de Oro-Mount Helix, California: USDA zone 10b, about 311 days between hard freezes, across 4K acres of town.
- USDA zone
- 10b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 3
- San Diego County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 11
- San Diego County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~311
- San Diego County normal — NOAA 1991–2020, nearest to this town
- Town area
- 4K 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 San Diego County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 10b is Casa de Oro-Mount Helix's average, not your lot's — a low corner or a tree line moves it. Against Casa de Oro-Mount Helix's 311-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Casa de Oro-Mount Helix
Each reading below is measured for Casa de Oro-Mount Helix itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsCasa de Oro-Mount Helix runs about 311 days between hard freezes (read from San Diego County, the closest normal to Casa de Oro-Mount Helix) — 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
MeasuredCasa de Oro-Mount Helix sits in USDA hardiness zone 10b.
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 Casa de Oro-Mount Helix is in
Casa de Oro-Mount Helix sits in the Southern California/Northern Baja Coast — EPA Level III, inside the wider Mediterranean California. That is read at Casa de Oro-Mount Helix's own centroid rather than borrowed from San Diego County.
What Grows in Casa de Oro-Mount Helix
Plants matched to Casa de Oro-Mount Helix's USDA zones 10b, 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 Casa de Oro-Mount Helix?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Jan 6; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 3 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 11 — long-season crops need about 90 days of runway, quick greens only 30. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.
Documented around Casa de Oro-Mount Helix
Spotted lanternfly documented 29 miles from Casa de Oro-Mount Helix, first recorded 2022. What to watch for.
What's on the federal record near Casa de Oro-Mount Helix
Closest first, within ~10 miles of Casa de Oro-Mount Helix. Listing isn't leaking, and distance isn't exposure.
- DOLORES STEVENBrownfields · 950 ft
- 4494 MONAHAN RD.Brownfields · 1400 ft
- 7-ELEVEN INC #13664Underground Storage Tanks · 2200 ft
- KELLY AUTOWORKS INC DBA GREG'S AUTOMOTIVE HELIXBrownfields · 2200 ft
- 7-ELEVEN INC #13664Brownfields · 2300 ft
- HELIX TEXACO SERVICEBrownfields · 2300 ft
- KRISTOPHER FROSTBrownfields · 2400 ft
- HEATHER HOVEBrownfields · 0.6 mi
- SAN MIGUEL FIRE DEPARTMENTBrownfields · 0.8 mi
- HELIX WATER DISTRICTBrownfields · 0.9 mi
- FOOTHILL METHODISTS CHURCHBrownfields · 0.9 mi
- RANDY KEITHBrownfields · 0.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Casa de Oro-Mount Helix'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 Casa de Oro-Mount Helix.
Total Sites
4,537
within ~10 miles of Casa de Oro-Mount Helix
Risk Level
Elevated
Highest-severity
5 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Casa de Oro-Mount Helix
Severity Distribution
within ~10 miles of Casa de Oro-Mount Helix
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Casa de Oro-Mount Helix, Brownfields runs higher than the national average — 4,078 sites within ~10 miles of Casa de Oro-Mount Helix. 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 Casa de Oro-Mount Helix
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 Casa de Oro-Mount Helix average
Your land is one point inside Casa de Oro-Mount Helix
Everything above resolves to Casa de Oro-Mount Helix as a whole — one PHZM band, read across 4K acres, with hard-freeze dates borrowed from San Diego 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 Casa de Oro-Mount Helix Average
Casa de Oro-Mount Helix Average
- ●USDA Zones 10b, averaged across Casa de Oro-Mount Helix
- ●One soil character for all of Casa de Oro-Mount Helix
- ●Frost dates read at Casa de Oro-Mount Helix's scale: Feb 3 to Dec 11
YOUR Parcel
- ✓Your exact zone, not Casa de Oro-Mount Helix's 10b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Casa de Oro-Mount Helix
Pull a site-specific report for your exact address in Casa de Oro-Mount Helix, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Casa de Oro-Mount Helix averages can't show:
We read public map data around Casa de Oro-Mount Helix — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Casa de Oro-Mount Helix average
How we know this about Casa de Oro-Mount Helix
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 San Diego 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 Casa de Oro-Mount Helix
When does frost risk typically end in Casa de Oro-Mount Helix?
The last hard freeze (28°F) in Casa de Oro-Mount Helix typically lands around Feb 3, 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 24.
When is the first frost in Casa de Oro-Mount Helix?
The first hard freeze (28°F) in Casa de Oro-Mount Helix typically arrives around Dec 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 27, so the watching starts about Nov 11 — about 311 days after the spring freeze cleared.
How long is the growing season in Casa de Oro-Mount Helix?
Measured between 28°F hard freezes, Casa de Oro-Mount Helix sees about 311 frost-free days — roughly Feb 3 through Dec 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 24 to Nov 27, about 276 days.
Is the soil safe to grow vegetables in Casa de Oro-Mount Helix?
The federal record around Casa de Oro-Mount Helix is a meaningful one — 4,537 documented sites, mostly Brownfields entries (4,078), the nearest Brownfields 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 Casa de Oro-Mount Helix?
From about Nov 11 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 11 (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 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Casa de Oro-Mount Helix's scale — its 10b band and its 311-day season. Your yard writes its own version of Casa de Oro-Mount Helix'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 Casa de Oro-Mount Helix’s own scale
5 of the readings below were taken at Casa de Oro-Mount Helix's own scale — the 4,385 acres it covers and 4,537 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- Casa de Oro-Mount Helix's own USDA hardiness band, zones 10bUSDA PHZM 2023
- 4,537 documented contamination sites on the federal record near Casa de Oro-Mount Helix, the closest Brownfields record about 0.2 miles out from the town centreFederal environmental registers
- Casa de Oro-Mount Helix's boundary and the 4,385 acres inside itUS Census TIGER/Line 2025
- The ecoregion at Casa de Oro-Mount Helix's own centroid, the Southern California/Northern Baja CoastUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Casa de Oro-Mount Helixlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The 28°F hard-freeze dates — Casa de Oro-Mount Helix has no normal of its own, so its county's is the closest measured readfrom San Diego County
- Soil character — no town-scale survey exists, so Casa de Oro-Mount Helix's 4,385 acres read through its county's SSURGO summaryfrom San Diego 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 San Diego 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 San Diego County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Casa de Oro-Mount Helix's 4,385 acreswhy one lot differs from the next →
- Which side of Casa de Oro-Mount Helix you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,385 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Casa de Oro-Mount Helix-wide figureread your own land →
More in California
Wider growing context
What grows across CaliforniaCasa de Oro-Mount Helix sits outside our named growing regions, so California as a whole is its closest context here.
Nearby growing guides