When to Plant Watermelon in Zone 12A
USDA Zone
12A
Cities Covered
25
Avg Last Frost
Thursday, January 1, 2026
Plant Type
Indoor Start
📅 Planting Calendar for Zone 12A
Start Seeds Indoors Thursday, December 4, 2025
Transplant Outdoors Thursday, January 15, 2026
Pro Tip: Start Watermelon seeds indoors 4 weeks before your last frost date for best results.
🌿 Plant Details
Scientific Name Citrullus lanatus
Days to Maturity 80 days
Sun Requirements Full Sun (8+ hours)
Plant Spacing 72" apart
Cities in Zone 12A
Aiea, Hawaii Anahola, Hawaii Haiku, Hawaii Hanalei, Hawaii Waikoloa, Hawaii Kalaheo, Hawaii Kapaa, Hawaii Kualapuu, Hawaii Kunia, Hawaii Kurtistown, Hawaii Lawai, Hawaii Lihue, Hawaii Makawao, Hawaii Makaweli, Hawaii Papaikou, Hawaii Pearl City, Hawaii Wahiawa, Hawaii Pukalani, Hawaii Mililani, Hawaii Kula, Hawaii Waialua, Hawaii Waipahu, Hawaii Wheeler Army Airfield, Hawaii Schofield Barracks, Hawaii Camp H M Smith, Hawaii
Other Plants for Zone 12A
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 Fennel 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 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 Watermelon in USDA Zone 12A
Watermelon (Citrullus lanatus) grows well in USDA Hardiness Zone 12A. This zone includes cities like Aiea, Anahola, Haiku and 22 more.
The average last frost date for Zone 12A is around Thursday, January 1, 2026. For best results, start your Watermelon seeds indoors around Thursday, December 4, 2025, then transplant outdoors around Thursday, January 15, 2026.
Expect to harvest your Watermelon approximately 80 days after planting.