Bay St. Louis, Mississippi, sits in USDA hardiness zone 9a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
On paper, artichoke, fig, california poppy, and cabbage all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Bay St. Louis, 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 Bay St. Louis 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 Bay St. Louis — soil, climate, flood, and parcel records. How we handle your address.
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Bay St. Louis — the short answer
Bay St. Louis, Mississippi: USDA zone 9a, about 304 days between hard freezes, across 9K acres of city.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 8
- Hancock County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 9
- Hancock County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~304
- Hancock 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 Hancock County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Bay St. Louis's average, not your lot's — a low corner or a tree line moves it. Against Bay St. Louis's 304-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Bay St. Louis
Each reading below is measured for Bay St. Louis itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsBay St. Louis runs about 304 days between hard freezes (read from Hancock County, the closest normal to Bay St. Louis) — 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
MeasuredBay St. Louis sits in USDA hardiness zone 9a.
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 Bay St. Louis is in
Bay St. Louis sits in the Southern Coastal Plain — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Bay St. Louis's own centroid rather than borrowed from Hancock County.
What Grows in Bay St. Louis
Every plant below cleared Bay St. Louis's own zone 9a and its 304-day season. Each card opens that plant's Mississippi profile. How we score.
Is it too late to plant in Bay St. Louis?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Jan 11; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 8 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 9 — 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 Bay St. Louis
Closest first, within ~10 miles of Bay St. Louis. Listing isn't leaking, and distance isn't exposure.
- BOUDINS WASTE AND RECYCLINGBrownfields · 1700 ft
- Chevron #41538Underground Storage Tanks · 2200 ft
- PERNICIARO AUTO REPAIRBrownfields · 2600 ft
- Charles Perniciaro Auto RepairUnderground Storage Tanks · 2600 ft
- OCHSNER MEDICAL CENTER - HANCOCKBrownfields · 0.5 mi
- Munro Tire SpotUnderground Storage Tanks · 0.5 mi
- Hancock Medical CenterUnderground Storage Tanks · 0.5 mi
- BAY ST. LOUIS HIGH SCHOOL MERCURYSuperfund · 0.6 mi
- Zodiac RestaurantUnderground Storage Tanks · 0.7 mi
- CASINO MAGIC CORPORATIONBrownfields · 0.7 mi
- 045K0473 HANCOCKNitrate · 0.7 mi
- TERRYS MARINE INCBrownfields · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Bay St. Louis'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 Bay St. Louis.
Total Sites
251
within ~10 miles of Bay St. Louis
Risk Level
Elevated
Highest-severity
5 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Bay St. Louis
Severity Distribution
within ~10 miles of Bay St. Louis
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Bay St. Louis, two things run higher than the national average within ~10 miles of Bay St. Louis — PFAS (5 sites) and Superfund (5 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Bay St. Louis
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 Bay St. Louis average
Your land is one point inside Bay St. Louis
Everything above resolves to Bay St. Louis as a whole — one PHZM band, read across 9K acres, with hard-freeze dates borrowed from Hancock 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 Bay St. Louis Average
Bay St. Louis Average
- ●USDA Zones 9a, averaged across Bay St. Louis
- ●One soil character for all of Bay St. Louis
- ●Frost dates read at Bay St. Louis's scale: Feb 8 to Dec 9
YOUR Parcel
- ✓Your exact zone, not Bay St. Louis's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Bay St. Louis
Pull a site-specific report for your exact address in Bay St. Louis, Mississippi — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Bay St. Louis averages can't show:
We read public map data around Bay St. Louis — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Bay St. Louis average
How we know this about Bay St. Louis
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 Hancock 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 Bay St. Louis
When does frost risk typically end in Bay St. Louis?
The last hard freeze (28°F) in Bay St. Louis typically lands around Feb 8, 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 Mar 1.
When is the first frost in Bay St. Louis?
The first hard freeze (28°F) in Bay St. Louis typically arrives around Dec 9, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 25, so the watching starts about Nov 9 — about 304 days after the spring freeze cleared.
How long is the growing season in Bay St. Louis?
Measured between 28°F hard freezes, Bay St. Louis sees about 304 frost-free days — roughly Feb 8 through Dec 9, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 1 to Nov 25, about 269 days.
Is the soil safe to grow vegetables in Bay St. Louis?
The federal record around Bay St. Louis is a meaningful one — 251 documented sites, mostly Underground Storage Tanks entries (106), the nearest Brownfields record about 0.3 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 Bay St. Louis?
From about Nov 9 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 9 (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 9. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Bay St. Louis's scale — its 9a band and its 304-day season. Your yard writes its own version of Bay St. Louis'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 Bay St. Louis’s own scale
5 of the readings below were taken at Bay St. Louis's own scale — the 9,403 acres it covers and 251 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Bay St. Louis's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 251 documented contamination sites on the federal record near Bay St. Louis, the closest Brownfields record about 0.3 miles out from the town centreFederal environmental registers
- Bay St. Louis's boundary and the 9,403 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~304-day seasonGrowable Ground crop-matching engine
- The ecoregion at Bay St. Louis's own centroid, the Southern Coastal PlainUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Bay St. Louis has no normal of its own, so its county's is the closest measured readfrom Hancock County
- Soil character — no town-scale survey exists, so Bay St. Louis's 9,403 acres read through its county's SSURGO summaryfrom Hancock County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Hancock County
- The growing challenges every Mississippi grower plans around — written at state scale, so they stay on the state guidefrom Mississippi
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Hancock County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Bay St. Louis's 9,403 acreswhy one lot differs from the next →
- Which side of Bay St. Louis you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 9,403 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.3 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 Bay St. Louis-wide figureread your own land →
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