If you’re a gardener in Southern California, knowing when to plant tomatoes is the key to a successful season. For optimal harvest timing, you need to sync your planting schedule with our unique coastal and inland climates.
Planting at the right moment avoids problems like frost damage, poor fruit set, and pest pressure. It sets your plants up for a long, productive season of delicious homegrown tomatoes. Let’s break down the best schedule for your specific area.
When To Plant Tomatoes In Southern California
There are two primary planting windows in SoCal: the main spring planting and a late summer planting for fall harvest. The exact dates depend heavily on whether you live near the coast or further inland.
Spring Planting: The Main Season
This is the most common and productive planting time. The goal is to get plants in the ground after the last frost date, when soil has warmed sufficiently.
- Coastal Zones (Los Angeles, San Diego, Orange County): Plant from late February through April. The mild, frost-free climate allows for an very early start.
- Inland Valleys & Warm Microclimates (San Fernando Valley, Inland Empire): Plant from mid-March through early May. Wait until the threat of frost has completely passed.
- High Desert Areas (Antelope Valley): Wait until late April or early May. Frost danger persists longer here.
Fall Planting: A Second Chance
Many gardeners don’t realize that Southern California’s long growing season allows for a second crop. Fall-planted tomatoes avoid the peak summer heat and produce into winter.
- Coastal Zones: Plant from late July through August.
- Inland Areas: Aim for late June through mid-July. The plants need to be established before the intense heat, but set fruit as temperatures cool in fall.
Using Soil Temperature as Your Guide
A more accurate method than calendar dates is checking your soil temperature. Tomato seeds germinate best in warm soil, and transplants establish faster.
- Use a soil thermometer at a depth of 2-4 inches.
- Ideal soil temperature for planting is consistently above 60°F, with 70°F being perfect.
- If soil is too cold, plants will be stunted and turn a purplish color.
Choosing the Right Tomato Varieties
Selecting types suited to your planting time and microclimate is crucial for optimal harvest timing.
For Early Spring & Coastal Gardens
Choose varieties that set fruit in cooler temperatures.
- Early Girl
- Stupice
- Siberia
- Most cherry tomato types
For Hot Inland Summers
Look for heat-set and disease-resistant varieties.
- Heatmaster
- Solar Fire
- Celebrity
- Arkansas Traveler
For Fall Planting
Opt for varieties with shorter “days to maturity” (DTM) to ensure fruit ripens before daylight hours shorten to much.
- Early Girl (again!)
- Juliet
- Patio Choice Yellow
- Many determinate (bush) types
Step-by-Step Planting for Success
Follow these steps to give your transplants the best possible start.
1. Site Selection & Soil Prep
Tomatoes need full sun—at least 8 hours of direct light. Prepare the soil 2-3 weeks before planting.
- Work in 3-4 inches of quality compost.
- Add a balanced, slow-release organic fertilizer according to package directions.
- Ensure the soil is well-draining.
2. Planting Your Transplants Correctly
Tomatoes are unique because they can develop roots all along their stems.
- Pinch off the lower leaves on your transplant, leaving the top 4-6 sets.
- Dig a hole deep enough to bury the stem up to those remaining leaves.
- Place the plant in the hole and backfill with soil. This encourages a massive, robust root system.
- Water deeply immediately after planting.
3. Support & Spacing
Install cages or stakes at planting time to avoid damaging roots later.
- Space determinate (bush) tomatoes 2-3 feet apart.
- Space indeterminate (vining) tomatoes 3-4 feet apart.
- Secure stems loosely to supports as they grow.
Seasonal Care for Optimal Harvests
Your care through the season directly impacts your harvest timing and yield.
Watering Deeply and Consistently
Inconsistent watering is a leading cause of problems like blossom end rot.
- Water deeply 1-2 times per week, depending on weather. The goal is moist, not soggy, soil.
- Use drip irrigation or soaker hoses to keep foliage dry and prevent disease.
- Mulch heavily with 3-4 inches of straw or shredded leaves to conserve moisture and regulate soil temperature.
Feeding Your Plants
Tomatoes are moderate feeders. To much nitrogen leads to leafy growth with little fruit.
- At planting: Use a balanced fertilizer or one slightly higher in phosphorus (the middle number).
- At first fruit set: Side-dress with a fertilizer higher in potassium (the last number) to support fruit development.
- Follow package instructions carefully—more is not better.
Managing Heat and Sun
Southern California’s intense summer sun can casue sunscald on fruit.
- Ensure plants have adequate leaf cover; avoid over-pruning.
- In extreme heat, provide temporary afternoon shade with a shade cloth.
- Maintain consistent watering during heat waves to reduce plant stress.
Troubleshooting Common Timing Issues
Even with perfect planting, challenges can arise. Here’s how to adjust.
Flowers But No Fruit (Blossom Drop)
This is often caused by temperature extremes.
- Night temps below 55°F or day temps above 90°F: Can interrupt pollination. Wait for milder weather; the next set of flowers should set fruit. Consider shade cloth for heat protection.
- Solution: Choose heat-set or cold-tolerant varieties next time, and plant in the optimal window.
Slow Ripening as Seasons Change
As fall days shorten and cool, ripening slows.
- Pinch off new flowers in early fall so the plant’s energy goes into existing fruit.
- If frost threatens, harvest mature green tomatoes and ripen them indoors in a paper bag with a banana.
Your Seasonal Tomato Calendar
A quick-reference guide to keep you on track.
- January-February: Start seeds indoors for spring planting (6-8 weeks before transplant date).
- Late Feb-April: Spring transplanting window. Harden off seedlings first.
- May-June: Maintain consistent watering and mulching as temperatures rise. Watch for pests.
- July: Begin planning and seeding for fall tomato crop, especially inland.
- August-September: Fall transplanting window. Provide shade for new transplants if heat persists.
- October-Onward: Harvest fall crop. Protect plants from early cool spells with frost cloth to extend harvest.
FAQ: Southern California Tomato Planting
Can I plant tomatoes in May in Southern California?
Yes, especially in coastal areas or if using transplants. Inland, it may be getting hot, so choose heat-tolerant varieties and be prepared to provide extra water and maybe afternoon shade.
What is the latest month to plant tomatoes?
For a fall harvest, aim to get transplants in the ground by early August on the coast and by mid-July inland. This gives plants enough time to mature fruit before cooler, shorter days arrive.
How do I get tomatoes to ripen faster?
Ensure they have adequate potassium, reduce watering slightly as fruit matures, and prune excess foliage to let sun reach the fruit. As season ends, you can also try gently lifting the plant’s roots to induce stress.
Why are my tomato plants growing tall but not producing?
This is often due to to much nitrogen fertilizer, insufficient sunlight (less than 6 hours), or temperatures being consistently outside the ideal range for fruit set (55-85°F). Review your feeding schedule and site choice.
Timing your tomato planting correctly in Southern California is the most effective way to ensure a bountiful, long-lasting harvest. By working with our distinct seasons—not against them—you can enjoy homegrown tomatoes for many months of the year. Pay close attention to your local microclimate, use soil temperature as a guide, and choose varieties wisely. With this plan, you’ll be harvesting perfect tomatoes right from your own garden.