When to Plant Fennel in Brownsville, Texas (78521)

Location

Brownsville, Texas

ZIP Code

78521

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.

Add to Calendar (.ics)

🌿 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 Brownsville?

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

🛒 Buy on Amazon 🌿 True Leaf Market

* Affiliate links — we may earn a small commission at no extra cost to you.

🤝 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

* Affiliate links — we may earn a small commission at no extra cost to you.

🌾 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 Brownsville, Texas? +

In Brownsville (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 Brownsville, Texas? +

The average last spring frost date for Brownsville, Texas (ZIP 78521) 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 Brownsville, that means you can expect harvest around Sunday, January 11, 2026 plus 80 days.

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

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

📚 More Fennel Planting Guides

🗺️

Fennel in Texas

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 10a Fennel Guide

All cities in your zone · Avg dates

→

Other Plants for Brownsville

Blackberry Blueberry Raspberry Strawberry Basil Chamomile Chives Cilantro Dill Lavender Lemon Balm Marjoram Mint Oregano Parsley Rosemary Sage Tarragon Thyme Acorn Squash Artichoke Arugula Asparagus Beefsteak Tomato Beet Bell Pepper Bok Choy Broccoli Brussels Sprout Butternut Squash Cabbage Cantaloupe Carrot Cauliflower Cayenne Pepper Celery Cherry Tomato Chili Pepper Collard Green Common Bean Cucumber Eggplant Endive Garlic Grape Tomato Green Bean Habanero Pepper Head Lettuce Heirloom Tomato Honeydew Melon Jalapeño Pepper Kale Kohlrabi Leaf Lettuce Leek Lima Bean Mustard Okra Onion Parsnip Pea Poblano Pepper Pole Pea Potato Pumpkin Radicchio Radish Rhubarb Roma Tomato Rutabaga Serrano Pepper Shallot Snap Pea Snow Pea Spaghetti Squash Spinach Squash Sweet Corn Sweet Potato Swiss Chard Tomato Turnip Watermelon Zucchini Sunflower Marigold Zinnia Nasturtium Cosmos Echinacea (Coneflower) Petunia Black-eyed Susan Apple Tree Pear Tree Peach Tree Plum Tree Sweet Cherry Tree Lemon Tree Borage Lemongrass Ginger Stevia Tomatillo Edamame Fava Bean Mâche Mizuna Sorrel Shishito Pepper Banana Pepper Watermelon Radish Napa Cabbage Popcorn Broccoli Raab Catnip Valerian Lemon Verbena Bee Balm Anise Lovage Chervil Summer Savory Dahlia Snapdragon Pansy Sweet Pea Morning Glory Hollyhock Larkspur Bachelor Button Columbine Impatiens Salvia (Annual) Sweet Alyssum Celosia Lupine Verbena Elderberry Grape Vine Red Currant Gooseberry Serviceberry Fig Tree Avocado Tree Persimmon Tree Olive Tree

Growing Fennel in Zone 10a

Fennel (Foeniculum vulgare) is a popular garden vegetable. In Brownsville, Texas, 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.