Knowing when to plant tomatoes in California is the first step to a great harvest. Our state’s diverse climates mean timing is everything, and getting it right gives your plants a strong start.
This guide breaks down the optimal planting windows for your specific region. We’ll cover how to prepare your soil, choose the right varieties, and protect young plants from surprise frosts.
When To Plant Tomatoes In California
California is split into distinct growing zones, each with its own ideal schedule. Planting at the correct time avoids cold soil and maximizes warm growing months.
Northern California Planting Schedule
This region includes areas like Sacramento, the Bay Area, and points north. Springs are cooler and wetter, so patience is key.
The safe window for transplanting seedlings outdoors is typically from late March through May. You can start seeds indoors 6-8 weeks before your planned transplant date.
- Coastal Areas (e.g., San Francisco): Plant from April to early June. Cool summer fog means slower growth, so choose cooler-climate varieties.
- Inland Valleys (e.g., Sacramento): Aim for mid-March to late April. The soil warms up quicker here away from the immediate coast.
Central California Planting Schedule
This prime growing region includes the Central Valley and coastal areas like San Luis Obispo. It offers a long, productive season.
You can usually plant from early March through April. Some gardeners even get a succesful fall crop by planting a second round in late July.
- Central Valley (e.g., Fresno, Bakersfield): Plant from early March. Be prepared to shade plants during intense summer heatwaves.
- Central Coast: Plant from April to May. Ocean breezes moderate temperatures for a steady, extended harvest.
Southern California Planting Schedule
With its very mild winters, Southern California has the longest tomato season. This includes Los Angeles, San Diego, and inland deserts.
The main planting season runs from late February through April. In many microclimates, you can also plant in late summer for a fall harvest.
- Coastal Southern California: Plant from February to April. Frost is rare, allowing for very early starts.
- Inland & Desert Areas (e.g., Riverside, Palm Springs): Plant in February or wait until late summer for a fall crop. Extreme summer heat can stress plants and halt fruit set.
How to Determine Your Exact Planting Date
Beyond general zones, use these two natural signals to pinpoint your best date.
Last Frost Date is Your Guide
Tomatoes are killed by frost. Your average last spring frost date is the single most important factor. You can find this date for your zip code from local agricultural extensions.
Plan to transplant your seedlings outdoors 1-2 weeks after this date. This ensures the soil has warmed up sufficiently.
Soil Temperature Matters Most
Tomato roots need warm soil to grow. Even if the air is warm, cold soil will shock plants and stunt them.
Use a soil thermometer. The ideal soil temperature for transplanting is consistently above 60°F (15°C), with 70°F (21°C) being optimal.
Preparing for Planting: A 5-Step Checklist
Good preparation makes all the difference. Follow these steps before your seedlings go in the ground.
- Choose the Right Variety: Match the tomato to your climate. Look for terms like “early season” for cooler areas or “heat-set” for hot valleys.
- Harden Off Seedlings: Over 7-10 days, gradually expose indoor-started plants to outdoor sun and wind. Start with just an hour of morning sun.
- Amend Your Soil: Work in 3-4 inches of compost or well-rotted manure. Tomatoes are heavy feeders and need well-draining soil.
- Plan for Support: Install cages or stakes at planting time to avoid damaging roots later. Its much easier to do it now.
- Check the Weather Forecast: Ensure no unexpected cold snaps are predicted for the week after planting. Have frost cloth ready just in case.
Common Planting Mistakes to Avoid
Avoid these pitfalls that can compromise your whole season.
- Planting Too Early: Eagerness leads to chilled, blue-looking plants that never thrive. Wait for warm soil.
- Ignoring Microclimates: Your yard may have a hot south-facing wall or a cold, shady corner. Observe these spots and plant accordingly.
- Overcrowding: Give plants plenty of space (usually 24-36 inches apart) for air circulation to prevent disease.
- Planting Too Deep (Initially): While you can bury stems later, at first plant only up to the first set of true leaves to avoid stem rot.
FAQ: Your California Tomato Questions Answered
Can I plant tomatoes in summer in California?
In most inland areas, summer planting is not advised due to extreme heat. However, along the cooler coast, you can plant in early summer. For a fall harvest in hotter areas, plant heat-tolerant varieties in late July.
What is the best month to plant tomatoes in Southern California?
For the main spring crop, March is often the ideal month across Southern California. This allows plants to establish before the peak summer heat arrives.
When should I start tomato seeds indoors in California?
Start seeds indoors 6 to 8 weeks before your planned outdoor transplant date. For a March transplant in Southern California, that means starting seeds in January. In cooler northern areas, start seeds in February for an April planting.
Is it to late to plant tomatoes in May?
In cooler coastal regions of Northern and Central California, May is perfectly fine. In hot inland valleys, May plantings will hit peak fruit set during the hottest months, which can cause problems. Choose quick-maturing or heat-loving varieties if planting late.
Final Tips for Success
Consistent watering is crucial, especially during fruit set. Water deeply and regularly to prevent blossom end rot. Mulch heavily around plants to conserve moisture and suppress weeds.
Pay attention to your plants signals. If growth seems slow early on, the soil might still be too cool. If flowers are dropping in summer heat, provide afternoon shade. With the right timing and care, you’ll be harvesting sun-warmed tomatoes for months.