When to Plant Onions in California
In a typical California location, start seeds indoors Nov 7 – Nov 21, then transplant outdoors Dec 19 – Jan 2. Across the state, the outdoor planting window starts as early as Dec 1 in San Mateo and as late as Apr 29 in Big Bear City. 103 cities in California are essentially frost-free and can plant on a year-round schedule.
Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.
Onions Planting Dates by City
| City | Start indoors | Transplant |
|---|---|---|
| Los Angeles | Frost-free: year-round planting | |
| San Diego | Frost-free: year-round planting | |
| San Jose | Oct 24 – Nov 7 | Dec 5 – Dec 19 |
| San Francisco | Frost-free: year-round planting | |
| Fresno | Nov 5 – Nov 19 | Dec 17 – Dec 31 |
| Sacramento | Nov 3 – Nov 17 | Dec 15 – Dec 29 |
| Long Beach | Frost-free: year-round planting | |
| Oakland | Frost-free: year-round planting | |
| Bakersfield | Nov 22 – Dec 6 | Jan 3 – Jan 17 |
| Anaheim | Frost-free: year-round planting | |
| Riverside | Oct 31 – Nov 14 | Dec 12 – Dec 26 |
| Santa Ana | Frost-free: year-round planting | |
| Stockton | Nov 27 – Dec 11 | Jan 8 – Jan 22 |
| Chula Vista | Frost-free: year-round planting | |
| Irvine | Frost-free: year-round planting | |
| Fremont | Oct 29 – Nov 12 | Dec 10 – Dec 24 |
| San Bernardino | Nov 18 – Dec 2 | Dec 30 – Jan 13 |
| Fontana | Nov 1 – Nov 15 | Dec 13 – Dec 27 |
| Modesto | Nov 22 – Dec 6 | Jan 3 – Jan 17 |
| Oxnard | Frost-free: year-round planting | |
| Moreno Valley | Nov 18 – Dec 2 | Dec 30 – Jan 13 |
| Huntington Beach | Frost-free: year-round planting | |
| Glendale | Oct 24 – Nov 7 | Dec 5 – Dec 19 |
| Santa Clarita | Oct 30 – Nov 13 | Dec 11 – Dec 25 |
| Santa Rosa | Dec 17 – Dec 31 | Jan 28 – Feb 11 |
| Oceanside | Frost-free: year-round planting | |
| Garden Grove | Frost-free: year-round planting | |
| Rancho Cucamonga | Oct 26 – Nov 9 | Dec 7 – Dec 21 |
| Ontario | Oct 26 – Nov 9 | Dec 7 – Dec 21 |
| Elk Grove | Nov 24 – Dec 8 | Jan 5 – Jan 19 |
Showing the 30 most populous of 530 California cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all California cities.
Frequently Asked Questions
When should I plant onions in California?
In a typical California location, start seeds indoors Nov 7 – Nov 21, then transplant outdoors Dec 19 – Jan 2. Across the state, the outdoor planting window starts as early as Dec 1 in San Mateo and as late as Apr 29 in Big Bear City. 103 cities in California are essentially frost-free and can plant on a year-round schedule.
When is the last frost in California?
The average last spring frost in California ranges from January 1 in Palm Springs to December 31 in Sunland, based on NOAA 1991–2020 climate normals.
How long do onions take to grow?
Onions typically take 90–120 days from planting to harvest. Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.
Other Crops in California
- Tomatoes
- Peppers
- Eggplant
- Cucumbers
- Zucchini
- Winter Squash
- Pumpkins
- Watermelon
- Cantaloupe
- Corn
- Green Beans
- Peas
- Lettuce
- Spinach
- Kale
- Arugula
- Swiss Chard
- Broccoli
- Cauliflower
- Cabbage
- Brussels Sprouts
- Carrots
- Beets
- Radishes
- Turnips
- Garlic
- Potatoes
- Sweet Potatoes
- Asparagus
- Basil
- Cilantro
- Parsley
- Dill
- Oregano
- Thyme
- Sunflowers
- Zinnias
- Marigolds
- Cosmos
- Nasturtiums
- Dahlias
When to plant onions in other states