When To Plant Lettuce In Southern California

If you’re wondering when to plant lettuce in Southern California, you’re in the right place. The good news is that our unique climate offers a long, productive season for growing crisp, fresh greens. You can enjoy homegrown lettuce for much of the year with the right timing.

Success comes from understanding our mild winters and warm summers. Lettuce is a cool-season crop, so avoiding the peak summer heat is key. Let’s break down the best planting windows to ensure your garden is a success.

This is your core planting guide. Southern California’s coastal and inland valleys have two primary planting seasons: late summer through winter for fall/winter harvests, and late winter through spring for spring harvests.

Fall & Winter Planting (The Main Season): Start seeds indoors or outdoors from late August through January. This is often the most successful period. Plants grow through the cool fall and mild winter.
Spring Planting: Plant from late January through early April. Get seeds in the ground as soon as the soil is workable to mature before the summer heat arrives.
Summer Planting: Generally not advised for most varieties. In cooler coastal zones, you can try heat-tolerant types (like ‘Jericho’ or ‘Summer Crisp’) in partial shade.

Understanding Your Microclimate

Southern California isn’t one climate. Your specific location makes a big difference.

Coastal Zones (Los Angeles, San Diego, Orange County coasts): Enjoy the longest season. You can often plant year-round with shade cloth in summer and choose of heat-tolerant varieties.
Inland Valleys & Deserts (San Fernando Valley, Riverside, Inland Empire): Winters are shorter and summers are hotter. Focus on fall and very early spring planting. You’ll need to provide afternoon shade for spring crops as temperatures rise.
High Desert Areas (Victorville, Palmdale): Frost is a real concern. Plant in early spring after the last frost and again in late summer for a fall harvest before first frost.

Step-by-Step Planting Guide

Follow these simple steps for a great harvest.

Choose Your Variety: Match the type to the season. Loose-leaf and butterhead types (like ‘Buttercrunch’) are forgiving. Romaine and crisphead need a bit more time and cooler weather.
Prepare the Soil: Lettuce needs fast-draining soil rich in organic matter. Work in 2-3 inches of compost before planting. The soil pH should be between 6.0 and 7.0.
Planting Seeds: Sow seeds 1/4 inch deep, spacing them about 1 inch apart. You can sow directly in the garden or start in trays. Keep the soil consistently moist for germination.
Thinning Seedlings: Once seedlings have a few leaves, thin them to the proper spacing: 4-6 inches for loose-leaf, 8-10 inches for romaine and butterhead, 12 inches for crisphead. The thinnings are edible!
Watering: Water regularly and evenly. Inconsistent watering leads to bitter leaves or bolting. Use drip irrigation or a soaker hose to keep leaves dry and prevent disease.
Feeding: Lettuce is a moderate feeder. A balanced, gentle organic fertilizer applied 3 weeks after transplanting is usually sufficent.

How to Avoid Bolting and Bitterness

Bolting (when the plant sends up a flower stalk) makes leaves bitter. It’s triggered by long days and high temperatures.

Plant on Time: This is the number one rule. Getting your crop to mature in cool weather is crucial.
Use Shade Cloth: As days lengthen and warm, use a 30-50% shade cloth to cool plants down.
Water Consistently: Never let the soil dry out completely. Mulch with straw or shredded leaves to retain moisture and keep soil cool.
Harvest in the Morning: Leaves are crispest and sweetest first thing in the day before the sun hits them.

Succession Planting for Continuous Harvest

Don’t plant all your seeds at once. For a steady supply, practice succession planting.

At each planting time (e.g., September), plant a small batch of seeds.
Then, every 2-3 weeks, plant another small batch.
This staggers maturity, so you have new heads comming ready every few weeks instead of all at once.

Common Pests and Problems

Watch out for these typical issues.

Slugs and Snails: They love tender lettuce. Use organic bait, beer traps, or hand-pick at night.
Aphids: Blast them off with a strong spray of water or use insecticidal soap.
Tip Burn: Brown edges on leaves often indicates inconsistent watering or a calcium deficiency. Ensure even moisture.
Bolting: As discussed, it’s a timing issue. Harvest the plant immediately if it starts to bolt, as leaves will quickly become inedible.

Recommended Lettuce Varieties for SoCal

Some varieties perform exceptionally well here across seasons.

Heat-Tolerant: ‘Jericho’ (Romaine), ‘New Red Fire’ (Leaf), ‘Summer Crisp’ varieties.
For Cool Seasons: ‘Buttercrunch’ (Butterhead), ‘Parris Island Cos’ (Romaine), ‘Black Seeded Simpson’ (Leaf).
Color & Mixes: Mesclun mixes, ‘Lollo Rossa’ (frilly red leaf), ‘Speckled Trout’ (beautiful spotted leaves).

FAQ: Planting Lettuce in Southern California

Can I grow lettuce in Southern California summer?
It’s challenging. In coastal areas, use heat-tolerant varieties and shade cloth. Inland, it’s usually best to take a break and focus on other summer crops.

What is the latest I can plant lettuce in Southern California?
For a winter harvest, you can plant as late as January in many areas. For spring, aim to have plants harvested by early June before intense heat.

Should I start lettuce seeds indoors or direct sow?
Both work. Direct sowing is easiest in fall and spring when soil temps are ideal. Starting indoors in summer (for fall transplants) can give seedlings a better start.

How often should I water lettuce in Southern California?
Water deeply when the top inch of soil feels dry. This may be every 2-3 days in warm weather, less in cool, cloudy weather. Container plants need water more frequently.

Why are my lettuce seeds not germinating?
Lettuce seeds need light and cool soil to germinate. If soil is too warm (over 70°F), they go dormant. Try pre-sprouting seeds on a damp paper towel in the fridge for a few days before planting in cooler months.

By following this calender and tips, you’ll be able to enjoy fresh, homegrown lettuce from your garden for many months of the year. Just remember the golden rule: keep it cool, keep it watered, and plant at the right time for your specific area.