When to Plant Fennel in Los Alamitos, California (90721)

Location

Los Alamitos, California

ZIP Code

90721

USDA Zone

10a

Last Frost

Sunday, January 25, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Sunday, December 28, 2025

Transplant Outdoors

Sunday, January 11, 2026

Based on last frost Sunday, January 25, 2026 · Zone 10a

Pro tip: Start Fennel seeds indoors 4 weeks before your last frost date, then transplant outdoors around Sunday, January 11, 2026.

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🌿 Plant Details

Scientific Name Foeniculum vulgare

Days to Maturity 80 days

☀️ Growing Requirements

☀️

Sun

Full Sun

💧

Water

Regular

Seeds typically germinate in 7-14 days

Ready to Plant Fennel in Los Alamitos?

Get your seeds now so they're ready by Sunday, December 28, 2025.

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🤝 Good Companions

Dill

🤝

Full Companion Planting Guide for Fennel

See which plants help Fennel thrive, which to keep away, and raised bed layout tips →

🛠️ Supplies You'll Need

🌱 Seed Starting Trays 🪴 Seed Starting Mix 💡 Grow Lights 🌡️ Heat Mat 🪵 Raised Garden Bed 🌍 Vegetable Garden Soil 🛠️ Hand Trowel Set 🚿 Watering Can

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🌾 Seed Saving Guide

🟢 Easy

✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Harvest umbels when seeds turn gray-green to brown — just before they drop.

Processing

Cut seed heads into a bag, dry 1–2 weeks, thresh to separate seeds.

Seed Viability

Up to 4 years when stored cool, dark, and dry.

Pro Tip

Fennel cross-pollinates with dill — keep at least 300 feet apart or sacrifice one crop when saving seed.

Frequently Asked Questions

When should I plant Fennel in Los Alamitos, California? +

In Los Alamitos (Zone 10a), start Fennel seeds indoors around Sunday, December 28, 2025 and transplant outdoors around Sunday, January 11, 2026.

What is the last frost date for Los Alamitos, California? +

The average last spring frost date for Los Alamitos, California (ZIP 90721) is around Sunday, January 25, 2026. This is based on NOAA climate normals for USDA Zone 10a.

How long does Fennel take to grow? +

Fennel typically matures in about 80 days from transplanting. In Los Alamitos, that means you can expect harvest around Sunday, January 11, 2026 plus 80 days.

Should I start Fennel indoors or direct sow in California? +

Fennel should be started indoors 4 weeks before your last frost date. In Los Alamitos, that means starting around Sunday, December 28, 2025.

📚 More Fennel Planting Guides

🗺️

Fennel in California

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 10a Fennel Guide

All cities in your zone · Avg dates

→

Other Plants for Los Alamitos

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Growing Fennel in Zone 10a

Fennel (Foeniculum vulgare) is a popular garden vegetable. In Los Alamitos, California, which is in USDA Hardiness Zone 10a, you should start seeds indoors around Sunday, December 28, 2025.

Your average last frost date is Sunday, January 25, 2026. Plan to transplant your Fennel seedlings outdoors around Sunday, January 11, 2026, about -2 weeks after your last frost date.