Barstow, CA planting calendar
- USDA zone
- 9a20 to 25 °F
- Last frost
- Feb 22avg, 32°F
- First frost
- Nov 23avg, 32°F
- Growing season
- 271days
Barstow, California is in USDA plant hardiness zone 9a. Its average last spring frost is around February 22 and the first fall frost around November 23, giving a growing season of about 271 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.
Barstow planting calendar
Each crop's windows are counted from Barstow'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 – Jan 11 | Mar 1 – Mar 8 | Apr 30 – May 20 | — |
| Pepper | Very tender | Jan 1 | Mar 8 – Mar 15 | May 7 – Jun 6 | — |
| Cucumber | Tender | Jan 25 – Feb 1 | Mar 1 – Mar 8 | Apr 20 – May 10 | — |
| Summer squash / zucchini | Tender | — | Mar 1 – Mar 8 | Apr 15 – Apr 30 | — |
| Bush bean | Tender | — | Mar 1 – Mar 8 | Apr 20 – Apr 30 | Sep 24 – Oct 4 |
| Sweet corn | Tender | — | Feb 22 – Mar 8 | Apr 23 – May 23 | — |
| Basil | Very tender | Jan 11 – Jan 25 | Mar 1 – Mar 8 | Mar 31 – Apr 15 | — |
| Lettuce | Half-hardy | Jan 11 – Jan 25 | Jan 25 – Feb 8 | Mar 11 – Mar 26 | Sep 10 – Sep 25 |
| Pea | Hardy | — | Jan 11 – Jan 25 | Mar 7 – Mar 22 | Aug 31 – Sep 15 |
| Spinach | Hardy | — | Jan 11 – Jan 25 | Feb 20 – Mar 2 | Sep 20 – Sep 30 |
| Carrot | Half-hardy | — | Feb 1 – Feb 8 | Apr 2 – Apr 22 | Aug 21 – Sep 10 |
| Broccoli | Half-hardy | Jan 1 – Jan 11 | Jan 25 – Feb 8 | Mar 21 – Apr 10 | Aug 26 – Sep 15 |
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 USC00040521. 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 | Mar 17 | Apr 14 | Nov 12 | Nov 26 | 237 |
| 32°F (freeze) | Feb 22 | Mar 24 | Nov 23 | Dec 8 | 271 |
| 28°F | Jan 30 | Feb 25 | Dec 6 | Dec 28 | 310 |
| 24°F | Jan 10 | Feb 7 | Dec 22 | Jan 19 | 346 |
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) | 6,141 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 9,440 | cool-season crops (brassicas, greens) |
Hardiness zone 9a
Barstow sits in USDA plant hardiness zone 9a on the 2023 map — meaning its average annual extreme minimum winter temperature is about 20 to 25 °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 9a, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Barstow?
- Barstow, California is in USDA plant hardiness zone 9a on the 2023 map (average annual extreme minimum temperature 20 to 25 °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 Barstow?
- The average (median) last spring frost at 32°F is around February 22, 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 24, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Barstow?
- The average first fall frost at 32°F is around November 23. That leaves a growing season of about 271 days between the average last spring and first fall frosts.
- When should I start tomatoes in Barstow?
- Start tomato seeds indoors about Jan 1 – Jan 11 and transplant them outside about Mar 1 – Mar 8, once the danger of frost has passed. Estimated first harvest is around Apr 30 – May 20.
- How long is the growing season in Barstow?
- About 271 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~February 22) and the average first fall frost (~November 23). 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 USC00040521 (Barstow, 8.3 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.