San Diego, Texas, sits in USDA hardiness zone 9b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
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 San Diego, 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 Diego 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 Diego — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
San Diego — the short answer
San Diego, Texas: USDA zone 9b, about 319 days between hard freezes, across 1K acres of city.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 29
- Duval County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 14
- Duval County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~319
- Duval County normal — NOAA 1991–2020, nearest to this town
- City area
- 1K 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 Duval County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is San Diego's average, not your lot's — a low corner or a tree line moves it. Against San Diego's 319-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in San Diego
Each reading below is measured for San Diego itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSan Diego runs about 319 days between hard freezes (read from Duval County, the closest normal to San Diego) — 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
MeasuredSan Diego 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 San Diego is in
San Diego sits in the Western Gulf Coastal Plain — EPA Level III, inside the wider Great Plains. That is read at San Diego's own centroid, and it is not what its county reads: Duval County is mostly Southern Texas Plains. The wider page above you is answering a different question about different ground.
What Grows in San Diego
Every plant below cleared San Diego's own zone 9b and its 319-day season. Each card opens that plant's Texas profile. How we score.
Is it too late to plant in San Diego?
For most of the year, no — what changes is which crops still fit the days remaining. 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 29 (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. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
What's on the federal record near San Diego
Closest first, within ~10 miles of San Diego. Listing isn't leaking, and distance isn't exposure.
- J RS SERVICE STATIONUnderground Storage Tanks · 1200 ft
- DANIELS AUTO CENTERUnderground Storage Tanks · 1300 ft
- KWIK PANTRYUnderground Storage Tanks · 1300 ft
- MORGANS GRILL & ICE HOUSEUnderground Storage Tanks · 1800 ft
- AYCOCK OILUnderground Storage Tanks · 2000 ft
- JB-84-15-702Nitrate · 2100 ft
- SUNNYS MINI MARTUnderground Storage Tanks · 2100 ft
- SAN DIEGO FOOD & SEEDUnderground Storage Tanks · 2100 ft
- CORNER STORE 1504Underground Storage Tanks · 2400 ft
- HUGO BERLANGAUnderground Storage Tanks · 0.5 mi
- SCHOOL BUSES TRANS BUILDINGUnderground Storage Tanks · 0.5 mi
- SANDIEGO FOOD MARTUnderground Storage Tanks · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from San Diego'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 Diego.
Sources Checked
within ~10 miles of San Diego
Severity Distribution
within ~10 miles of San Diego
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around San Diego, Underground Storage Tanks runs higher than the national average — 95 sites within ~10 miles of San Diego. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in San Diego
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 Diego average
Your land is one point inside San Diego
Everything above resolves to San Diego as a whole — one PHZM band, read across 1K acres, with hard-freeze dates borrowed from Duval 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 Diego Average
San Diego Average
- ●USDA Zones 9b, averaged across San Diego
- ●One soil character for all of San Diego
- ●Frost dates read at San Diego's scale: Jan 29 to Dec 14
YOUR Parcel
- ✓Your exact zone, not San Diego's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in San Diego
Pull a site-specific report for your exact address in San Diego, Texas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that San Diego averages can't show:
We read public map data around San Diego — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the San Diego average
How we know this about San Diego
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 Duval 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 Diego
When does frost risk typically end in San Diego?
The last hard freeze (28°F) in San Diego typically lands around Jan 29, 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 19.
When is the first frost in San Diego?
The first hard freeze (28°F) in San Diego 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 319 days after the spring freeze cleared.
How long is the growing season in San Diego?
Measured between 28°F hard freezes, San Diego sees about 319 frost-free days — roughly Jan 29 through Dec 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 19 to Nov 30, about 284 days.
Is the soil safe to grow vegetables in San Diego?
The federal record around San Diego shows 118 documented sites, mostly Underground Storage Tanks entries (95), the nearest Underground Storage Tanks record about 0.2 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 San Diego?
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 San Diego's scale — its 9b band and its 319-day season. Your yard writes its own version of San Diego'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 Diego’s own scale
5 of the readings below were taken at San Diego's own scale — the 1,217 acres it covers and 118 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- San Diego's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 118 documented contamination sites on the federal record near San Diego, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- San Diego's boundary and the 1,217 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~319-day seasonGrowable Ground crop-matching engine
- San Diego sits in the Western Gulf Coastal Plain — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — San Diego has no normal of its own, so its county's is the closest measured readfrom Duval County
- Soil character — no town-scale survey exists, so San Diego's 1,217 acres read through its county's SSURGO summaryfrom Duval County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Duval County
- The growing challenges every Texas grower plans around — written at state scale, so they stay on the state guidefrom Texas
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Duval County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among San Diego's 1,217 acreswhy one lot differs from the next →
- Which side of San Diego you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,217 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 San Diego-wide figureread your own land →