USDA zone 9b in Louisiana
USDA plant hardiness zone 9b covers 21 locations across Louisiana (average annual extreme minimum 25 to 30 °F): Bayou Blue, LA, Berwick, LA, Carlyss, LA, Chalmette, LA, Delacroix, LA, Dulac, LA, and 15 more. Average last spring frost across this group ranges January 22 (New Orleans) to February 24 (New Orleans), and growing seasons run 281–348 days (New Orleans to New Orleans) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Louisiana location's own frost dates; the printable planting calendar uses Bayou Blue, this group's median-season location.
- USDA zone
- 9b25 to 30 °F
- Last frost range
- Jan 22–Feb 24avg, 32°F
- First frost range
- Jan 1–Dec 31avg, 32°F
- Growing season range
- 281–348days
Locations in this group
Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|
| Bayou Blue * | Raceland, Dulac, Houma, Schriever, Gray, Bayou Cane, +4 more | Thibodaux 4 Se | Feb 5 | Dec 14 | 311 |
| Berwick | Bayou L'Ourse, Patterson, Amelia | Morgan City | Jan 30 | Jan 1 | 335 |
| Carlyss | Prien, Hayes | Lake Charles | Feb 14 | Dec 7 | 299 |
| Chalmette | — | Terrytown 3s | Feb 1 | Dec 31 | 330 |
| Delacroix | — | St Bernard | Feb 4 | Dec 15 | 312 |
| Dulac | Cut Off, Galliano, Larose, Bourg, Montegut, Lockport | Galliano | Feb 8 | Dec 19 | 311 |
| Erath | Lydia, Delcambre | New Iberia Acadiana Rgnl Ap | Feb 14 | Dec 5 | 298 |
| Franklin | Charenton, Baldwin, Centerville | Franklin 3 Nw | Feb 11 | Dec 8 | 303 |
| Hackberry | — | Hackberry 8 Ssw | Feb 3 | Dec 24 | 323 |
| Hayes | — | Lake Arthur 7 Sw | Feb 10 | Dec 11 | 307 |
| Hayes | Lake Arthur | Rockefeller Wl Refuge | Feb 2 | Dec 23 | 323 |
| Jeanerette | — | Jeanerette 5 Nw | Feb 15 | Dec 3 | 294 |
| Kaplan | — | Leland Bowman Lock | Feb 17 | Dec 5 | 298 |
| Lafitte | Estelle, Barataria, Delacroix | Marrero 9 Ssw | Feb 10 | Dec 12 | 306 |
| Luling | Metairie, Laplace, Kenner, Bayou Gauche, St. Rose, Paradis, +5 more | New Orleans Intl Ap | Jan 30 | Dec 31 | 333 |
| Metairie | Marrero, Harvey, Avondale, Bridge, Gretna, Terrytown, +1 more | New Orleans Audubon | Jan 24 | Jan 2 | 341 |
| New Orleans | Metairie, Meraux, Violet, Arabi | New Orleans Lakefront Ap | Jan 22 | Jan 5 | 348 |
| New Orleans | — | Slidell | Feb 24 | Dec 1 | 281 |
| Pointe a la Hache | — | Lsu Citrus Rsch Stn | Feb 3 | Dec 28 | 327 |
| Reserve | Edgard, South Vacherie | Reserve | Feb 9 | Dec 14 | 308 |
| Supreme | Pierre Part | Donaldsonville 4 Sw | Feb 21 | Dec 5 | 291 |
* Bayou Blue is this group's median-season location — the calendar below is computed from its data.
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Planting calendar (Bayou Blue, representative)
Computed from Bayou Blue's average frost dates — the median-season location in this Louisianazone 9b group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Jan 1 | Feb 12 – Feb 19 | Apr 13 – May 3 | — | matures comfortably |
| Pepper | Very tender | Jan 1 | Feb 19 – Feb 26 | Apr 20 – May 20 | — | matures comfortably |
| Cucumber | Tender | Jan 8 – Jan 15 | Feb 12 – Feb 19 | Apr 3 – Apr 23 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | Feb 12 – Feb 19 | Mar 29 – Apr 13 | — | matures comfortably |
| Bush bean | Tender | — | Feb 12 – Feb 19 | Apr 3 – Apr 13 | Oct 15 – Oct 25 | matures comfortably |
| Sweet corn | Tender | — | Feb 5 – Feb 19 | Apr 6 – May 6 | — | matures comfortably |
| Basil | Very tender | Jan 1 – Jan 8 | Feb 12 – Feb 19 | Mar 14 – Mar 29 | — | matures comfortably |
| Lettuce | Half-hardy | Jan 1 – Jan 8 | Jan 8 – Jan 22 | Feb 22 – Mar 9 | Oct 1 – Oct 16 | matures comfortably |
| Pea | Hardy | — | Jan 1 – Jan 8 | Feb 25 – Mar 12 | Sep 21 – Oct 6 | matures comfortably |
| Spinach | Hardy | — | Jan 1 – Jan 8 | Feb 10 – Feb 20 | Oct 11 – Oct 21 | matures comfortably |
| Carrot | Half-hardy | — | Jan 15 – Jan 22 | Mar 16 – Apr 5 | Sep 11 – Oct 1 | matures comfortably |
| Broccoli | Half-hardy | Jan 1 | Jan 8 – Jan 22 | Mar 4 – Mar 24 | Sep 16 – Oct 6 | matures comfortably |
Which crops fit this growing season
Using Bayou Blue's own 311-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (Bayou Blue)
From NOAA's 1991–2020 Climate Normals at station USC00169013. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | Feb 27 | Mar 21 | Nov 29 | Dec 23 | 277 |
| 32°F (freeze) | Feb 5 | Mar 7 | Dec 14 | Jan 15 | 311 |
| 28°F | Jan 23 | Feb 21 | Jan 1 | Feb 1 | 346 |
| 24°F | Jan 13 | Feb 3 | Jan 7 | Jan 31 | 365 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 21 locations is 7,261; Bayou Blue's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 7,517 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 11,026 | cool-season crops (brassicas, greens) |
Hardiness zone 9b in Louisiana
Zone 9b means an average annual extreme minimum winter temperature of about 25 to 30 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Louisiana spans 4 hardiness zones in this dataset — see all Louisiana locations for the full range, including zones8b, 9a, 10a.
Explore zone 9b in other states at zone 9b, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 9b mean in Louisiana?
- Zone 9b means an average annual extreme minimum winter temperature of 25 to 30 °F — the standard USDA measure of which perennials survive winter. 21 locations in Louisiana fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in Louisiana's zone 9b is the growing season longest?
- New Orleans runs the longest season on this page at about 348 days; New Orleans is shortest at about 281 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in Louisiana's zone 9b?
- Using Bayou Blue's frost dates (this page's median-season location): start seeds indoors about Jan 1, then transplant outside about Feb 12 – Feb 19. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in Louisiana's zone 9b have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 21 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.