Chalmette, LA planting calendar
- USDA zone
- 9b25 to 30 °F
- Last frost
- Feb 1avg, 32°F
- First frost
- Dec 31avg, 32°F
- Growing season
- 330days
Chalmette, Louisiana is in USDA plant hardiness zone 9b. Its average last spring frost is around February 1 and the first fall frost around December 31, giving a growing season of about 330 days (NOAA 1991–2020 normals, 32°F, median). Start tender crops like tomatoes and peppers indoors weeks before the last frost and set them out afterward; sow hardy crops such as peas, spinach, and lettuce before it. The planner below turns those frost dates into a printable per-crop planting calendar.
Chalmette planting calendar
Each crop's windows are counted from Chalmette's average frost dates. 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.
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting |
|---|---|---|---|---|---|
| Tomato | Tender | Jan 1 | Feb 8 – Feb 15 | Apr 9 – Apr 29 | — |
| Pepper | Very tender | Jan 1 | Feb 15 – Feb 22 | Apr 16 – May 16 | — |
| Cucumber | Tender | Jan 4 – Jan 11 | Feb 8 – Feb 15 | Mar 30 – Apr 19 | — |
| Summer squash / zucchini | Tender | — | Feb 8 – Feb 15 | Mar 25 – Apr 9 | — |
| Bush bean | Tender | — | Feb 8 – Feb 15 | Mar 30 – Apr 9 | Nov 1 – Nov 11 |
| Sweet corn | Tender | — | Feb 1 – Feb 15 | Apr 2 – May 2 | — |
| Basil | Very tender | Jan 1 – Jan 4 | Feb 8 – Feb 15 | Mar 10 – Mar 25 | — |
| Lettuce | Half-hardy | Jan 1 – Jan 4 | Jan 4 – Jan 18 | Feb 18 – Mar 5 | Oct 18 – Nov 2 |
| Pea | Hardy | — | Jan 1 – Jan 4 | Feb 25 – Mar 12 | Oct 8 – Oct 23 |
| Spinach | Hardy | — | Jan 1 – Jan 4 | Feb 10 – Feb 20 | Oct 28 – Nov 7 |
| Carrot | Half-hardy | — | Jan 11 – Jan 18 | Mar 12 – Apr 1 | Sep 28 – Oct 18 |
| Broccoli | Half-hardy | Jan 1 | Jan 4 – Jan 18 | Feb 28 – Mar 20 | Oct 3 – Oct 23 |
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.
Frost & freeze dates
From NOAA's 1991–2020 Climate Normals at station USC00168941. 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 (p10 for spring, p90 for fall) — 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 22 | Mar 16 | Dec 9 | Jan 7 | 292 |
| 32°F (freeze) | Feb 1 | Mar 6 | Dec 31 | Jan 29 | 330 |
| 28°F | Jan 23 | Feb 26 | Jan 8 | Feb 9 | 361 |
| 24°F | Jan 17 | Feb 6 | Jan 11 | Feb 4 | 365 |
32°F is the standard "freeze" line that damages tender crops; lighter 36°F frost can nip the most cold-sensitive plants, while hardy crops shrug off light frost down toward 28°F. Use the threshold that matches what you are protecting.
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. Warm-season crops need a long, warm GDD total; a short, cool GDD total favors greens and brassicas.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 7,565 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 11,082 | cool-season crops (brassicas, greens) |
Hardiness zone 9b
Chalmette sits in USDA plant hardiness zone 9b on the 2023 map — meaning its average annual extreme minimum winter temperature is about 25 to 30 °F. That number 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.
Explore more places in zone 9b, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Chalmette?
- Chalmette, Louisiana is in USDA plant hardiness zone 9b on the 2023 map (average annual extreme minimum temperature 25 to 30 °F) — from the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. See the methodology page for sources.
- When is the last frost in Chalmette?
- The average (median) last spring frost at 32°F is around February 1, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as March 6, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Chalmette?
- The average first fall frost at 32°F is around December 31. That leaves a growing season of about 330 days between the average last spring and first fall frosts.
- When should I start tomatoes in Chalmette?
- Start tomato seeds indoors about Jan 1 and transplant them outside about Feb 8 – Feb 15, once the danger of frost has passed. Estimated first harvest is around Apr 9 – Apr 29.
- How long is the growing season in Chalmette?
- About 330 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~February 1) and the average first fall frost (~December 31). Cold-hardy crops extend usable time at both ends; frost-tender crops fit inside it.
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020 for station USC00168941 (Terrytown 3s, 7.3 km away). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to this 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.