Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for Sulphur, LA

Sulphur, LA is in USDA zones 9a to 9b across its 3 ZIP codes. The median last spring frost is March 2 and the first fall frost November 25.

Sulphur on the zone map

Outlined: its 2 ZIP code areas · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zones9a–9b20 to 30 °F

ZIP codes3

Last frostMar 2

First frostNov 25

Growing season267 days

9a 2 ZIPs 9b 1 ZIP

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Sulphur, LA…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Sulphur, LA

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMarch 2median — 50% chance of a later frost

Safe for tender plantsMarch 26only 10% chance of frost after

First fall frostNovember 25median — 10% chance by Nov 3

Growing season267 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 11 and returns around December 10.

From the NOAA station Moss Bluff 2 Nnw, LA, elevation 26 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in Sulphur

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 19 – Feb 2

SpinachSow outdoors · Jan 19 – Feb 9

Broccoli, cabbageStart indoors · Dec 22 – Jan 5

Broccoli, cabbageTransplant · Feb 9 – Feb 23

Onion setsPlant outdoors · Feb 2 – Feb 16

PotatoesPlant outdoors · Feb 9 – Feb 23

LettuceSow outdoors · Feb 2 – Feb 16

Carrots, beetsSow outdoors · Feb 9 – Feb 23

TomatoesStart indoors · Jan 5 – Jan 19

TomatoesTransplant · Mar 9 – Mar 23

Peppers, eggplantStart indoors · Dec 22 – Jan 5

Peppers, eggplantTransplant · Mar 16 – Mar 30

BeansSow outdoors · Mar 9 – Mar 23

Sweet cornSow outdoors · Mar 9 – Mar 23

Cucumbers, squashSow outdoors · Mar 9 – Mar 23

Fall lettuce, spinachSow outdoors · Sep 30 – Oct 14

GarlicPlant cloves · Nov 11 – Dec 16

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 2) and first fall frost (Nov 25) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 70663 came on Jan 11 — 15 days earlier than the 1991–2020 average (Jan 26).

average
Jan 262026
Jan 11

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 9a in Louisiana

517 plants native to the lower 48 states, recorded in Louisiana, and rated by the USDA to survive 20 °F or colder — the bottom of zone 9a. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Sulphur, LA.

Soil in Sulphur, LA

The soil mapped at the center of ZIP 70663 is Kinder — silt loam, poorly drained.

TextureSilt loama good balance for most vegetables

pH4.5strongly acidic; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter2.8%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classprime farmlandUSDA classification

Map unit: Kinder-Gist complex, 0 to 1 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 70663; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Sulphur, LA

Summer high92 °Faverage high, July

Winter low40 °Faverage low, January

Hot days93days a year at 90 °F or more

Freezing nights25nights a year at 32 °F or less

Growing degree days6,811base 50 °F — the season’s usable heat

Longest day14 h 06 mindaylight on June 21

Shortest day10 h 12 mindaylight on December 21

Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb

Precipitation63.6 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Moss Bluff 2 Nnw, LA (12 mi away); precipitation: Sulphur, LA (4 mi away). Daylight is calculated from latitude.

ZIP codes in Sulphur

Louisiana planting zones →

Questions about Sulphur

What planting zone is Sulphur, LA?

Sulphur, LA is in USDA hardiness zones 9a to 9b on the 2023 map (9a: 20 to 25 °F; 9b: 25 to 30 °F).

When is the last frost in Sulphur, LA?

The median last spring frost is March 2 and the median first fall frost is November 25 (NOAA 1991–2020 normals, Moss Bluff 2 Nnw station).

When can I plant a garden in Sulphur, LA?

Cool-season crops like peas and spinach go in around Jan 19 – Feb 9; tomatoes, peppers, beans and squash after about Mar 9, once frost risk has passed.

What kind of onions grow in Sulphur, LA?

Short-day onions: the longest day is 14 h 06 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

How much rain and snow does Sulphur, LA get?

About 63.6 inches of precipitation a year (NOAA 1991–2020 normals).