Hahnville, Louisiana, sits in USDA hardiness zone 9b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
On paper, okra, meyer lemon, california poppy, and artichoke all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Hahnville, 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 Hahnville 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 Hahnville — soil, climate, flood, and parcel records. How we handle your address.
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Hahnville — the short answer
Hahnville, Louisiana: USDA zone 9b, about 337 days between hard freezes, across 4K acres of town.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 18
- St. Charles Parish normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 21
- St. Charles Parish normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~337
- St. Charles Parish 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 St. Charles Parish’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Hahnville's average, not your lot's — a low corner or a tree line moves it. Against Hahnville's 337-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Hahnville
Each reading below is measured for Hahnville itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsHahnville runs about 337 days between hard freezes (read from St. Charles Parish, the closest normal to Hahnville) — 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
MeasuredHahnville 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 Hahnville is in
Hahnville sits in the Mississippi Alluvial Plain — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Hahnville's own centroid rather than borrowed from St. Charles Parish.
What Grows in Hahnville
Every plant below cleared Hahnville's own zone 9b and its 337-day season. Each card opens that plant's Louisiana profile. How we score.
Is it too late to plant in Hahnville?
Usually not — gardeners here simply switch what goes in the ground as the season moves. 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 18 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 21 — 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 Hahnville
Closest first, within ~10 miles of Hahnville. Listing isn't leaking, and distance isn't exposure.
- MCKENZIE TANK LINES INCBrownfields · 0.6 mi
- BRIGHTWAY SERVICE INCBrownfields · 0.7 mi
- FLEETCLEAN SYSTEMS INCBrownfields · 0.7 mi
- Hahnville Coastal Waste Services Facility - Coastal Waste Services IncUnderground Storage Tanks · 0.8 mi
- MOTION INDUSTRIES INCBrownfields · 0.8 mi
- ST CHARLES RECYCLING INCBrownfields · 0.8 mi
- CIVIL CONSTRUCTION CO INCBrownfields · 0.9 mi
- Birdies #5Underground Storage Tanks · 1.0 mi
- SC-148Nitrate · 1.0 mi
- GO OILBrownfields · 1.1 mi
- MADERES GARAGE INCBrownfields · 1.1 mi
- St Charles Parish General Government BuildingsUnderground Storage Tanks · 1.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Hahnville'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 Hahnville.
Total Sites
900
within ~10 miles of Hahnville
Risk Level
Elevated
Highest-severity
5 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Hahnville
Severity Distribution
within ~10 miles of Hahnville
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Hahnville, two things run higher than the national average within ~10 miles of Hahnville — Brownfields (476 sites) and Toxics Release Inventory (56 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Hahnville
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 Hahnville average
Your land is one point inside Hahnville
Everything above resolves to Hahnville as a whole — one PHZM band, read across 4K acres, with hard-freeze dates borrowed from St. Charles Parish’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 Hahnville Average
Hahnville Average
- ●USDA Zones 9b, averaged across Hahnville
- ●One soil character for all of Hahnville
- ●Frost dates read at Hahnville's scale: Jan 18 to Dec 21
YOUR Parcel
- ✓Your exact zone, not Hahnville's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Hahnville
Pull a site-specific report for your exact address in Hahnville, Louisiana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Hahnville averages can't show:
We read public map data around Hahnville — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Hahnville average
How we know this about Hahnville
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 St. Charles Parish’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 Hahnville
When does frost risk typically end in Hahnville?
The last hard freeze (28°F) in Hahnville typically lands around Jan 18, 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 8.
When is the first frost in Hahnville?
The first hard freeze (28°F) in Hahnville typically arrives around Dec 21, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 7, so the watching starts about Nov 21 — about 337 days after the spring freeze cleared.
How long is the growing season in Hahnville?
Measured between 28°F hard freezes, Hahnville sees about 337 frost-free days — roughly Jan 18 through Dec 21, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 8 to Dec 7, about 302 days.
Is the soil safe to grow vegetables in Hahnville?
The federal record around Hahnville is a meaningful one — 900 documented sites, mostly Brownfields entries (476), the nearest Brownfields 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 Hahnville?
From about Nov 21 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 21 (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 21. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Hahnville's scale — its 9b band and its 337-day season. Your yard writes its own version of Hahnville'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 Hahnville’s own scale
5 of the readings below were taken at Hahnville's own scale — the 3,557 acres it covers and 900 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Hahnville's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 900 documented contamination sites on the federal record near Hahnville, the closest Brownfields record about 0.6 miles out from the town centreFederal environmental registers
- Hahnville's boundary and the 3,557 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~337-day seasonGrowable Ground crop-matching engine
- The ecoregion at Hahnville's own centroid, the Mississippi Alluvial PlainUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Hahnville has no normal of its own, so its county's is the closest measured readfrom St. Charles Parish
- Soil character — no town-scale survey exists, so Hahnville's 3,557 acres read through its county's SSURGO summaryfrom St. Charles County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom St. Charles County
- The growing challenges every Louisiana grower plans around — written at state scale, so they stay on the state guidefrom Louisiana
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom St. Charles County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Hahnville's 3,557 acreswhy one lot differs from the next →
- Which side of Hahnville you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,557 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Hahnville-wide figureread your own land →