San Luis Obispo, California, sits in USDA hardiness zone 10a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Growers here do well with avocado, meyer lemon, tomato, and artichoke — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in San Luis Obispo, 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 San Luis Obispo 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 San Luis Obispo — soil, climate, flood, and parcel records. How we handle your address.
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San Luis Obispo — the short answer
San Luis Obispo, California: USDA zone 10a, about 228 days between hard freezes, across 9K acres of city.
- USDA zone
- 10a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 1
- San Luis Obispo County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Nov 15
- San Luis Obispo County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~228
- San Luis Obispo County normal — NOAA 1991–2020, nearest to this town
- City area
- 9K 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 Luis Obispo County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 10a is San Luis Obispo's average, not your lot's — a low corner or a tree line moves it. Against San Luis Obispo's 228-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in San Luis Obispo
Each reading below is measured for San Luis Obispo itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSan Luis Obispo runs about 228 days between hard freezes (read from San Luis Obispo County, the closest normal to San Luis Obispo) — 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
MeasuredSan Luis Obispo sits in USDA hardiness zone 10a.
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 San Luis Obispo is in
San Luis Obispo sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at San Luis Obispo's own centroid rather than borrowed from San Luis Obispo County.
What Grows in San Luis Obispo
Plants matched to San Luis Obispo's USDA zones 10a, 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 San Luis Obispo?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 4; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 1 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 15 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
What's on the federal record near San Luis Obispo
Closest first, within ~10 miles of San Luis Obispo. Listing isn't leaking, and distance isn't exposure.
- ARCHITECTURAL IRON WORKS INCBrownfields · 300 ft
- KAIROS MFG INC DBA ARCHITECTURAL IRON WORKSBrownfields · 600 ft
- BAILEY BRIDGES INCORPORATEDBrownfields · 600 ft
- POOR RICHARD'S PRESSBrownfields · 750 ft
- Caltrans-District 5 OfficeUnderground Storage Tanks · 900 ft
- CHARTER COMMUNICATIONS SAN LUIS OBISPOBrownfields · 950 ft
- PRP COMPANIESBrownfields · 1100 ft
- JOHN'S ValeroUnderground Storage Tanks · 1100 ft
- WRONA'S QUALITY AUTO REPAIRBrownfields · 1100 ft
- JIFFY LUBE PCJL INCBrownfields · 1100 ft
- JOHN'S 76Brownfields · 1100 ft
- NEWPORT PACIFIC/CIRUS DEVELOPMENTBrownfields · 1200 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from San Luis Obispo'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 San Luis Obispo.
Total Sites
704
within ~10 miles of San Luis Obispo
Risk Level
Elevated
Highest-severity
7 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of San Luis Obispo
Severity Distribution
within ~10 miles of San Luis Obispo
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around San Luis Obispo, two things run higher than the national average within ~10 miles of San Luis Obispo — Mining (86 sites) and Brownfields (558 sites). That's not a problem with your land — it's information about 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.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in San Luis Obispo
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 San Luis Obispo average
Your land is one point inside San Luis Obispo
Everything above resolves to San Luis Obispo as a whole — one PHZM band, read across 9K acres, with hard-freeze dates borrowed from San Luis Obispo County’s record because no 30-year normal resolves at this city’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 city 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 San Luis Obispo Average
San Luis Obispo Average
- ●USDA Zones 10a, averaged across San Luis Obispo
- ●One soil character for all of San Luis Obispo
- ●Frost dates read at San Luis Obispo's scale: Apr 1 to Nov 15
YOUR Parcel
- ✓Your exact zone, not San Luis Obispo's 10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in San Luis Obispo
Pull a site-specific report for your exact address in San Luis Obispo, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that San Luis Obispo averages can't show:
We read public map data around San Luis Obispo — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the San Luis Obispo average
How we know this about San Luis Obispo
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at San Luis Obispo 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 city grain anywhere on this page — there is no city-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 San Luis Obispo
When does frost risk typically end in San Luis Obispo?
The last hard freeze (28°F) in San Luis Obispo typically lands around Apr 1, 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 22.
When is the first frost in San Luis Obispo?
The first hard freeze (28°F) in San Luis Obispo typically arrives around Nov 15, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 1, so the watching starts about Oct 16 — about 228 days after the spring freeze cleared.
How long is the growing season in San Luis Obispo?
Measured between 28°F hard freezes, San Luis Obispo sees about 228 frost-free days — roughly Apr 1 through Nov 15, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 22 to Nov 1, about 193 days.
Is the soil safe to grow vegetables in San Luis Obispo?
The federal record around San Luis Obispo is a meaningful one — 704 documented sites, mostly Brownfields entries (558), the nearest Brownfields record under a tenth of a mile 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 San Luis Obispo?
From about Oct 16 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 15 (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 15. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at San Luis Obispo's scale — its 10a band and its 228-day season. Your yard writes its own version of San Luis Obispo'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 San Luis Obispo’s own scale
4 of the readings below were taken at San Luis Obispo's own scale — the 8,730 acres it covers and 704 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- San Luis Obispo's own USDA hardiness band, zones 10aUSDA PHZM 2023
- 704 documented contamination sites on the federal record near San Luis Obispo, the closest Brownfields record under a tenth of a mile out from the town centreFederal environmental registers
- San Luis Obispo's boundary and the 8,730 acres inside itUS Census TIGER/Line 2025
- The ecoregion at San Luis Obispo'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 — San Luis Obispo has no normal of its own, so its county's is the closest measured readfrom San Luis Obispo County
- Soil character — no town-scale survey exists, so San Luis Obispo's 8,730 acres read through its county's SSURGO summaryfrom San Luis Obispo 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 Luis Obispo 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 Luis Obispo County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among San Luis Obispo's 8,730 acreswhy one lot differs from the next →
- Which side of San Luis Obispo you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 8,730 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record under a tenth of a mile 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 San Luis Obispo-wide figureread your own land →