Benicia, CA planting zone & frost dates
Benicia is in USDA hardiness zone 9b. The last spring frost usually comes around February 28 and the first fall frost around November 22, for a growing season of about 266 days.
Planting calendar for Benicia
Dates are counted from the average last spring frost (February 28) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Jan 3 – Jan 17 Transplant outdoors: Mar 7 – Mar 14 |
| Peppers | Start seeds indoors: Dec 20 – Jan 3 Transplant outdoors: Mar 14 – Mar 21 |
| Eggplant | Start seeds indoors: Dec 20 – Jan 3 Transplant outdoors: Mar 14 – Mar 21 |
| Broccoli | Start seeds indoors: Dec 20 – Jan 3 Transplant outdoors: Jan 31 – Feb 14 |
| Cabbage | Start seeds indoors: Dec 20 – Jan 3 Transplant outdoors: Jan 31 – Feb 14 |
| Onions (sets) | Plant outdoors: Jan 31 – Feb 14 |
| Peas | Sow outdoors: Jan 17 – Jan 31 |
| Spinach | Sow outdoors: Jan 17 – Jan 31 |
| Lettuce | Sow outdoors: Jan 31 – Feb 14 |
| Carrots | Sow outdoors: Jan 31 – Feb 14 |
| Potatoes | Plant outdoors: Jan 31 – Feb 14 |
| Beans | Sow outdoors: Mar 7 – Mar 14 |
| Sweet corn | Sow outdoors: Mar 7 – Mar 14 |
| Cucumbers | Sow outdoors: Mar 7 – Mar 14 |
| Squash & zucchini | Sow outdoors: Mar 7 – Mar 14 |
| Basil | Start seeds indoors: Jan 17 – Jan 31 Transplant outdoors: Mar 7 – Mar 14 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 27 (8 weeks before the average first fall frost on Nov 22).
Useful for zone 9b gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Shade cloth — for hot summers
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Jan 29 | Feb 28 | Apr 5 |
| First 32°F frost in fall is before | Dec 10 | Nov 22 | Nov 7 |
How to read it: in spring there is a 10% chance of a frost after April 5, so that is a safe date for tender plants. In fall there is a 10% chance of frost before November 7. A hard freeze (28°F) usually ends around January 23.
Hardiness zone by ZIP code in Benicia
- 94510 zone 9b
Nearby cities
- Martinez zone 9b, last frost Feb 28
- Vallejo zone 9b, last frost Jan 17
- Hercules zone 9b, last frost Jan 17
- Pleasant Hill zone 9b, last frost Jan 7
- Concord zone 9b, last frost Jan 9
- Pinole zone 9b
- El Sobrante zone 9b
- American Canyon zone 9b, last frost Mar 5
Questions
What growing zone is Benicia, CA?
Benicia is in USDA Plant Hardiness Zone 9b (average extreme winter low 25°F to 30°F), according to the USDA 2023 map.
When is the last frost in Benicia?
The average last spring frost (32°F) in Benicia is February 28. There is still a 10% chance of frost until April 5.
When can I plant tomatoes in Benicia?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Mar 7 – Mar 14. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Martinez Wtp, CA (USC00045378), 5.6 km (3.5 mi) from the city center, elevation 12 m, based on 18 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.