Heidelberg, Texas, sits in USDA hardiness zone 10a — 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 Heidelberg, 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 Heidelberg 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 Heidelberg — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Heidelberg — the short answer
Heidelberg, Texas: USDA zone 10a, about 341 days between hard freezes, across 2K acres of town.
- USDA zone
- 10a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 16
- Hidalgo County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 23
- Hidalgo County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~341
- Hidalgo County normal — NOAA 1991–2020, nearest to this town
- Town area
- 2K 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 Hidalgo County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 10a is Heidelberg's average, not your lot's — a low corner or a tree line moves it. Against Heidelberg's 341-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Heidelberg
Each reading below is measured for Heidelberg itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsHeidelberg runs about 341 days between hard freezes (read from Hidalgo County, the closest normal to Heidelberg) — 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
MeasuredHeidelberg 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 Heidelberg is in
Heidelberg sits in the Western Gulf Coastal Plain — EPA Level III, inside the wider Great Plains. That is read at Heidelberg's own centroid rather than borrowed from Hidalgo County.
What Grows in Heidelberg
Every plant below cleared Heidelberg's own zone 10a and its 341-day season. Each card opens that plant's Texas profile. How we score.
Is it too late to plant in Heidelberg?
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 16 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 23 — 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 Heidelberg
Closest first, within ~10 miles of Heidelberg. Listing isn't leaking, and distance isn't exposure.
- BM FOOD MART 3Underground Storage Tanks · 0.6 mi
- 7-ELEVEN STORE 40717Underground Storage Tanks · 1.7 mi
- CITY OF MERCEDESPFAS · 1.7 mi
- BORDENSUnderground Storage Tanks · 1.8 mi
- LITTLE KOUNTRY STOREUnderground Storage Tanks · 1.9 mi
- QUICK PIC DRIVE INUnderground Storage Tanks · 2.0 mi
- TEN TEN GROCERYUnderground Storage Tanks · 2.5 mi
- XOOM MR300Underground Storage Tanks · 2.5 mi
- QUICK PIC 3Underground Storage Tanks · 2.5 mi
- JOES TIRES REPAIRUnderground Storage Tanks · 2.5 mi
- T-MARTUnderground Storage Tanks · 2.6 mi
- CHIQUITA MELONUnderground Storage Tanks · 2.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Heidelberg'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 Heidelberg.
Total Sites
275
within ~10 miles of Heidelberg
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Heidelberg
Severity Distribution
within ~10 miles of Heidelberg
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Heidelberg, two things run higher than the national average within ~10 miles of Heidelberg — PFAS (8 sites) and Underground Storage Tanks (214 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Heidelberg
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 Heidelberg average
Your land is one point inside Heidelberg
Everything above resolves to Heidelberg as a whole — one PHZM band, read across 2K acres, with hard-freeze dates borrowed from Hidalgo 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 Heidelberg Average
Heidelberg Average
- ●USDA Zones 10a, averaged across Heidelberg
- ●One soil character for all of Heidelberg
- ●Frost dates read at Heidelberg's scale: Jan 16 to Dec 23
YOUR Parcel
- ✓Your exact zone, not Heidelberg's 10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Heidelberg
Pull a site-specific report for your exact address in Heidelberg, Texas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Heidelberg averages can't show:
We read public map data around Heidelberg — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Heidelberg average
How we know this about Heidelberg
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 Hidalgo 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 Heidelberg
When does frost risk typically end in Heidelberg?
The last hard freeze (28°F) in Heidelberg typically lands around Jan 16, 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 6.
When is the first frost in Heidelberg?
The first hard freeze (28°F) in Heidelberg typically arrives around Dec 23, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 9, so the watching starts about Nov 23 — about 341 days after the spring freeze cleared.
How long is the growing season in Heidelberg?
Measured between 28°F hard freezes, Heidelberg sees about 341 frost-free days — roughly Jan 16 through Dec 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 6 to Dec 9, about 306 days.
Is the soil safe to grow vegetables in Heidelberg?
The federal record around Heidelberg is a meaningful one — 275 documented sites, mostly Underground Storage Tanks entries (214), the nearest Underground Storage Tanks record about 0.6 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 Heidelberg?
From about Nov 23 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 23 (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 23. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Heidelberg's scale — its 10a band and its 341-day season. Your yard writes its own version of Heidelberg'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 Heidelberg’s own scale
5 of the readings below were taken at Heidelberg's own scale — the 1,690 acres it covers and 275 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Heidelberg's own USDA hardiness band, zones 10aUSDA PHZM 2023
- 275 documented contamination sites on the federal record near Heidelberg, the closest Underground Storage Tanks record about 0.6 miles out from the town centreFederal environmental registers
- Heidelberg's boundary and the 1,690 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 10a and a ~341-day seasonGrowable Ground crop-matching engine
- The ecoregion at Heidelberg's own centroid, the Western Gulf Coastal PlainUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Heidelberg has no normal of its own, so its county's is the closest measured readfrom Hidalgo County
- Soil character — no town-scale survey exists, so Heidelberg's 1,690 acres read through its county's SSURGO summaryfrom Hidalgo County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Hidalgo 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 Hidalgo County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Heidelberg's 1,690 acreswhy one lot differs from the next →
- Which side of Heidelberg you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,690 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.6 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 Heidelberg-wide figureread your own land →
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