La Mesa, CA planting zone & frost dates
La Mesa is in USDA hardiness zone 10b. The last spring frost usually comes around January 6 and the first fall frost around December 21, for a growing season of about 350 days.
Planting calendar for La Mesa
Dates are counted from the average last spring frost (January 6) 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: Nov 11 – Nov 25 Transplant outdoors: Jan 13 – Jan 20 |
| Peppers | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Jan 20 – Jan 27 |
| Eggplant | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Jan 20 – Jan 27 |
| Broccoli | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Dec 9 – Dec 23 |
| Cabbage | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Dec 9 – Dec 23 |
| Onions (sets) | Plant outdoors: Dec 9 – Dec 23 |
| Peas | Sow outdoors: Nov 25 – Dec 9 |
| Spinach | Sow outdoors: Nov 25 – Dec 9 |
| Lettuce | Sow outdoors: Dec 9 – Dec 23 |
| Carrots | Sow outdoors: Dec 9 – Dec 23 |
| Potatoes | Plant outdoors: Dec 9 – Dec 23 |
| Beans | Sow outdoors: Jan 13 – Jan 20 |
| Sweet corn | Sow outdoors: Jan 13 – Jan 20 |
| Cucumbers | Sow outdoors: Jan 13 – Jan 20 |
| Squash & zucchini | Sow outdoors: Jan 13 – Jan 20 |
| Basil | Start seeds indoors: Nov 25 – Dec 9 Transplant outdoors: Jan 13 – Jan 20 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 26 (8 weeks before the average first fall frost on Dec 21).
Useful for zone 10b 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
As an Amazon Associate, FrostZoneMap earns from qualifying purchases, at no extra cost to you.
Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Dec 13 | Jan 6 | Feb 7 |
| First 32°F frost in fall is before | Jan 15 | Dec 21 | Dec 1 |
How to read it: in spring there is a 10% chance of a frost after February 7, so that is a safe date for tender plants. In fall there is a 10% chance of frost before December 1. A hard freeze (28°F) usually ends around December 31.
Hardiness zone by ZIP code in La Mesa
- 91941 zone 10b
- 91942 zone 10b
- 91943 zone 10b
- 91944 zone 10b
Nearby cities
- Lemon Grove zone 10b, last frost Jan 6
- Spring Valley zone 10b, last frost Jan 6
- Casa de Oro-Mount Helix zone 10b, last frost Jan 6
- La Presa zone 10b
- El Cajon zone 10a, last frost Jan 6
- Santee zone 10a, last frost Jan 6
- Rancho San Diego zone 10b, last frost Jan 6
- Bostonia zone 10a, last frost Jan 6
Questions
What growing zone is La Mesa, CA?
La Mesa is in USDA Plant Hardiness Zone 10b (average extreme winter low 35°F to 40°F), according to the USDA 2023 map.
When is the last frost in La Mesa?
The average last spring frost (32°F) in La Mesa is January 6. There is still a 10% chance of frost until February 7.
When can I plant tomatoes in La Mesa?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Jan 13 – Jan 20. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station El Cajon, CA (USC00042706), 9.6 km (6.0 mi) from the city center, elevation 151 m, based on 27 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.