When To Plant Broccoli In California

If you’re planning your California vegetable garden, knowing when to plant broccoli is the key to a great harvest. This cool-season crop thrives in our unique climate, but timing is everything to avoid bolting or poor head formation.

California’s long growing season and varied climate zones offer two main planting windows: late summer for a fall/winter harvest and late winter for a spring harvest. Getting your timing right means you’ll enjoy tender, sweet heads instead of bitter, flowering plants. Let’s break down the optimal schedule for your area.

This heading is your golden rule. Broccoli prefers to mature in cool weather, so you plant it so that the heads develop when daytime temperatures are consistently between 60°F and 70°F. In most of California, this means two primary planting times.

California’s Two Main Broccoli Planting Seasons

You have two excellent chances to grow broccoli each year.

For a Fall/Winter Harvest: Plant in late summer, from July to September. This is often the best and easiest season. Seeds sown in summer heat grow into mature plants as the weather cools, yielding sweeter heads after a light frost.
For a Spring Harvest: Plant in late winter, from January to March. You’ll need to get transplants in the ground early enough so they mature before the summer heat arrives, which can cause bolting.

Broccoli Planting Calendar by California Region

Our state’s microclimates require slight adjustments to the general rule.

Northern California & Coastal Areas

Cooler summers and mild winters allow for a long, productive season.

Fall Planting: Start seeds indoors May to June. Transplant outdoors July to August.
Spring Planting: Start seeds indoors December to January. Transplant outdoors February to March.

Central Valley & Inland Areas

Hot summers are a challenge, making fall planting more reliable.

Fall Planting: Start seeds indoors June to July. Transplant outdoors August to September. Provide afternoon shade for young transplants.
Spring Planting: This is trickier. Start seeds indoors in December for January transplant, aiming for harvest by May before extreme heat.

Southern California (Low-Desert & Interior)

The key is to grow broccoli through the mild winter.

Fall/Winter Planting: This is your main season. Start seeds indoors September to October. Transplant outdoors October to November for harvest through winter.
Spring Planting: Only in the coolest coastal spots. Plant by January at the latest.

Step-by-Step: How to Plant Your Broccoli

Once you’ve got your date, follow these steps for success.

1. Starting Seeds vs. Buying Transplants

You can do either, but starting from seed gives you more variety choices.

Starting Seeds Indoors: Begin 6-8 weeks before your planned transplant date. Use a seed-starting mix and provide plenty of light.
Direct Sowing: In cooler coastal climates, you can sow seeds directly in late summer or early spring. It’s less reliable in hot inland areas.
Using Transplants: A great shortcut! Choose stocky, green plants with no yellowing. Avoid any that already have tiny flower buds.

2. Preparing Your Garden Bed

Broccoli is a heavy feeder. Prepare the soil well.

Choose a spot with full sun (at least 6 hours).
Work in 3-4 inches of compost or well-rotted manure.
Mix in a balanced organic fertilizer according to package directions.
Ensure the soil is well-draining; raised beds are excellent.

3. Transplanting Seedlings Outdoors

Harden Off: For 7-10 days, gradually expose indoor-started seedlings to outdoor conditions.
Plant: Set transplants slightly deeper than they were in their pot. Space plants 18-24 inches apart in rows 3 feet apart.
Water Deeply: Water immediately after planting to settle the soil.
Mulch: Apply a 2-3 inch layer of straw or shredded leaves to conserve moisture and keep roots cool.

Essential Care Tips for California Gardeners

Consistent care prevents problems and boosts your yield.

Watering and Feeding

Broccoli needs steady moisture, especially as heads form.

Water deeply 1-2 times per week, aiming for 1-1.5 inches of water. Drip irrigation is ideal.
Side-dress with a high-nitrogen fertilizer 3 weeks after transplanting and again when heads begin to form.
Uneven watering can lead to hollow stems or poor head development, so try to keep a schedule.

Managing Pests and Problems

Watch for these common issues.

Aphids: Blast them off with water or use insecticidal soap.
Cabbage Loopers/Worms: Handpick or use BT (Bacillus thuringiensis), an organic bacterial spray.
Bolting: If the plant flowers prematurely, it’s usually due to stress from heat or lack of water. Sticking to the correct planting window is the best prevention.

Harvesting Your Broccoli

Harvest time is the best reward! Here’s how to do it right.

Cut the central head when the buds are tight and firm, before any yellow flowers begin to open. Use a sharp knife and make a slanted cut about 5-6 inches down the stem.
After the main head is harvested, many varieties produce smaller side shoots for weeks. Keep watering and you’ll get a continous yield.
Don’t wait to long to harvest; over-mature heads become loose and bitter.

Recommended Broccoli Varieties for California

Some varieties perform exceptionally well here.

‘Calabrese’: A classic, reliable heirloom for fall planting.
‘Green Goliath’ or ‘Packman’: Fast-maturing, good for spring crops where the season is short.
‘Belstar’: Excellent heat tolerance, great for inland valleys.
‘Purple Sprouting’: Produces many small, tender side shoots over a long period, perfect for mild-winter areas.

FAQ: Broccoli Planting in California

Can I grow broccoli year-round in California?

In the coolest coastal zones, you can succession plant for nearly year-round harvest. In most areas, you’ll rely on the two main seasons (fall and spring) to avoid summer heat and winter freezes.

What if my broccoli starts to flower?

If the head bolts (flowers), harvest it immediately—it will be edible but tougher. The plant is signaling it’s under stress, usually from temperatures that are to high. Compost the plant and try again in the next season.

How do I protect broccoli from pests naturally?

Use floating row covers right after planting to exclude moths and butterflies. Encourage beneficial insects like ladybugs and lacewings by planting flowers nearby. Check the undersides of leaves regularly.

Can I plant broccoli in partial shade?

Broccoli needs full sun for best growth. In very hot inland areas, afternoon shade can help prevent bolting in a spring planting, but 6 hours of direct sun is still a minimum.

When is to late to plant broccoli in Southern California?

For a winter harvest, aim to get transplants in the ground by November. Planting later risks that plants won’t mature properly if cool weather doesn’t arrive or if an early heat wave hits in spring.