When to Plant Fennel in Zone 12B
USDA Zone
12B
Cities Covered
53
Avg Last Frost
Friday, January 1, 2027
Plant Type
Indoor Start
📅 Planting Calendar for Zone 12B
Start Seeds Indoors Friday, December 4, 2026
Transplant Outdoors Friday, December 18, 2026
Pro Tip: Start Fennel seeds indoors 4 weeks before your last frost date for best results.
🌿 Plant Details
Scientific Name Foeniculum vulgare
Days to Maturity 80 days
Sun Requirements Full Sun
🤝 Companion Plants for Fennel
Good Companions
Dill
Cities in Zone 12B
Captain Cook, Hawaii Eleele, Hawaii Ewa Beach, Hawaii Kapolei, Hawaii Hakalau, Hawaii Haleiwa, Hawaii Hanamaulu, Hawaii Hanapepe, Hawaii Hauula, Hawaii Hawi, Hawaii Hilo, Hawaii Princeville, Hawaii Honomu, Hawaii Hoolehua, Hawaii Kaaawa, Hawaii Kahuku, Hawaii Kahului, Hawaii Kailua, Hawaii Kailua Kona, Hawaii Kalaupapa, Hawaii Kaneohe, Hawaii Kaumakani, Hawaii Kaunakakai, Hawaii Keaau, Hawaii Kealakekua, Hawaii Kealia, Hawaii Kekaha, Hawaii Kihei, Hawaii Kilauea, Hawaii Kapaau, Hawaii Koloa, Hawaii Lahaina, Hawaii Laie, Hawaii Lanai City, Hawaii Laupahoehoe, Hawaii Maunaloa, Hawaii Naalehu, Hawaii Pahala, Hawaii Pahoa, Hawaii Paia, Hawaii Papaaloa, Hawaii Pepeekeo, Hawaii Puunene, Hawaii Waianae, Hawaii Wailuku, Hawaii Waimanalo, Hawaii Waimea, Hawaii Honolulu, Hawaii Hickam Afb, Hawaii Fort Shafter, Hawaii Tripler Army Medical Ctr, Hawaii Pearl Harbor, Hawaii Wake Island, Hawaii
Other Plants for Zone 12B
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
Browse Other Zones
Growing Fennel in USDA Zone 12B
Fennel (Foeniculum vulgare) grows well in USDA Hardiness Zone 12B. This zone includes cities like Captain Cook, Eleele, Ewa Beach and 50 more.
The average last frost date for Zone 12B is around Friday, January 1, 2027. For best results, start your Fennel seeds indoors around Friday, December 4, 2026, then transplant outdoors around Friday, December 18, 2026.
Expect to harvest your Fennel approximately 80 days after planting.