San Carlos I, Texas, sits in USDA hardiness zone 9b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Growers here do well with okra, meyer lemon, california poppy, and artichoke — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in San Carlos I, 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 Carlos I 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 Carlos I — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
San Carlos I — the short answer
San Carlos I, Texas: USDA zone 9b, about 326 days between hard freezes, across 85 acres of town.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 25
- Webb County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 17
- Webb County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~326
- Webb County normal — NOAA 1991–2020, nearest to this town
- Town area
- 85 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 Webb County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is San Carlos I's average, not your lot's — a low corner or a tree line moves it. Against San Carlos I's 326-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in San Carlos I
Each reading below is measured for San Carlos I itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSan Carlos I runs about 326 days between hard freezes (read from Webb County, the closest normal to San Carlos I) — 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 Carlos I 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 Carlos I is in
San Carlos I sits in the Southern Texas Plains — EPA Level III, inside the wider Great Plains. That is read at San Carlos I's own centroid rather than borrowed from Webb County.
What Grows in San Carlos I
Every plant below cleared San Carlos I's own zone 9b and its 326-day season. Each card opens that plant's Texas profile. How we score.
Is it too late to plant in San Carlos I?
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 25 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 17 — long-season crops need about 90 days of runway, quick greens only 30. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
What's on the federal record near San Carlos I
Closest first, within ~10 miles of San Carlos I. Listing isn't leaking, and distance isn't exposure.
- BROTHERS MATERIALS LTDBrownfields · 1.8 mi
- CITY OF LAREDO LANDFILLBrownfields · 2.0 mi
- CHIEFS FOOD MART & RESTAURANTUnderground Storage Tanks · 2.9 mi
- YZ-85-37-205Nitrate · 3.0 mi
- MOLINAS COUNTRY STOREUnderground Storage Tanks · 3.0 mi
- TRACTOR SUPPLY #1534Brownfields · 3.6 mi
- 7-ELEVEN STORE 40925Underground Storage Tanks · 3.7 mi
- 7-ELEVEN STORE 40923Underground Storage Tanks · 4.0 mi
- YZ-85-37-206Nitrate · 4.1 mi
- WEBB COUNTY RD & BRIDGE DEPTUnderground Storage Tanks · 4.4 mi
- AZTEC FUELS INCBrownfields · 4.6 mi
- ARGUINDEGUI PUMP N SHOP 26Underground Storage Tanks · 4.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from San Carlos I'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 Carlos I.
Total Sites
415
within ~10 miles of San Carlos I
Risk Level
Elevated
Highest-severity
4 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of San Carlos I
Severity Distribution
within ~10 miles of San Carlos I
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around San Carlos I, Underground Storage Tanks runs higher than the national average — 275 sites within ~10 miles of San Carlos I. 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 Carlos I
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 Carlos I average
Your land is one point inside San Carlos I
Everything above resolves to San Carlos I as a whole — one PHZM band, read across 85 acres, with hard-freeze dates borrowed from Webb 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 San Carlos I Average
San Carlos I Average
- ●USDA Zones 9b, averaged across San Carlos I
- ●One soil character for all of San Carlos I
- ●Frost dates read at San Carlos I's scale: Jan 25 to Dec 17
YOUR Parcel
- ✓Your exact zone, not San Carlos I's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in San Carlos I
Pull a site-specific report for your exact address in San Carlos I, Texas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that San Carlos I averages can't show:
We read public map data around San Carlos I — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the San Carlos I average
How we know this about San Carlos I
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 Webb 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 San Carlos I
When does frost risk typically end in San Carlos I?
The last hard freeze (28°F) in San Carlos I typically lands around Jan 25, 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 15.
When is the first frost in San Carlos I?
The first hard freeze (28°F) in San Carlos I typically arrives around Dec 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 3, so the watching starts about Nov 17 — about 326 days after the spring freeze cleared.
How long is the growing season in San Carlos I?
Measured between 28°F hard freezes, San Carlos I sees about 326 frost-free days — roughly Jan 25 through Dec 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 15 to Dec 3, about 291 days.
Is the soil safe to grow vegetables in San Carlos I?
The federal record around San Carlos I is a meaningful one — 415 documented sites, mostly Underground Storage Tanks entries (275), the nearest Brownfields record about 1.8 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 San Carlos I?
From about Nov 17 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 17 (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 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at San Carlos I's scale — its 9b band and its 326-day season. Your yard writes its own version of San Carlos I'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 Carlos I’s own scale
5 of the readings below were taken at San Carlos I's own scale — the 85 acres it covers and 415 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- San Carlos I's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 415 documented contamination sites on the federal record near San Carlos I, the closest Brownfields record about 1.8 miles out from the town centreFederal environmental registers
- San Carlos I's boundary and the 85 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~326-day seasonGrowable Ground crop-matching engine
- The ecoregion at San Carlos I's own centroid, the Southern Texas PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — San Carlos I has no normal of its own, so its county's is the closest measured readfrom Webb County
- Soil character — no town-scale survey exists, so San Carlos I's 85 acres read through its county's SSURGO summaryfrom Webb County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Webb 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 Webb County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among San Carlos I's 85 acreswhy one lot differs from the next →
- Which side of San Carlos I you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 85 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 San Carlos I-wide figureread your own land →