When to Plant Petunia in Colby, Wisconsin (54421)

Location

Colby, Wisconsin

ZIP Code

54421

USDA Zone

Last Frost

Tuesday, May 5, 2026

📅 Planting Calendar

Start Seeds Indoors Tuesday, February 24, 2026

Transplant Outdoors Tuesday, May 19, 2026

Pro Tip: Start Petunia seeds indoors 10 weeks before your last frost date, then transplant outdoors around Tuesday, May 19, 2026.

🌿 Plant Details

Scientific Name Petunia × hybrida

Days to Maturity 75 days

Mature Height 6-18"

Spread 18"

Type Annual

☀️ Growing Requirements

☀️

Sun

Full Sun (6-8 hours)

💧

Water

Moderate (1 inch/week)

↔️

Spacing

12" apart

🌱

Planting Depth

0.13" deep

Seeds typically germinate in 7-14 days

Ready to Plant Petunia in Colby?

Get your seeds now so they're ready by Tuesday, February 24, 2026.

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🤝 Good Companions

TomatoBasilMarigold

⚠️ Avoid Planting Near

Fennel

Other Plants for Colby

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 Watermelon Zucchini Sunflower Marigold Zinnia Nasturtium Cosmos Echinacea (Coneflower) 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 Petunia in Zone 4b

Petunia (Petunia × hybrida) is a popular garden vegetable. In Colby, Wisconsin, which is in USDA Hardiness Zone 4b, you should start seeds indoors around Tuesday, February 24, 2026.

Your average last frost date is Tuesday, May 5, 2026. Plan to transplant your Petunia seedlings outdoors around Tuesday, May 19, 2026, about 2 weeks after your last frost date.