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When to Plant Cosmos in Delaware

🌱

Direct Sow Outdoors

Sunday, April 5, 2026

State

Delaware

USDA Zones

7a, 7b, 8a

Avg Last Frost

Sunday, April 5, 2026

Cities Covered

57

Delaware Planting Schedule by Zone

Delaware spans 3 zones — find yours below for the most accurate dates.

Zone Last Frost Direct Sow
7a Friday, April 10, 2026 Friday, April 10, 2026
7b Sunday, April 5, 2026 Sunday, April 5, 2026
8a Friday, March 20, 2026 Friday, March 20, 2026

Dates based on average last frost. Check your local forecast before planting.

🌿 About Cosmos

Scientific Name Cosmos bipinnatus
Days to Maturity 60 days
Plant Type Annual
Sun Full Sun (6-8 hours)
Water Low-Moderate
Spacing 18" apart

🤝 Companion Plants for Cosmos

Good Companions

CornSquashTomato
See the full companion planting guide for Cosmos →

Growing Cosmos in Delaware: Complete Guide

Cosmos (Cosmos bipinnatus) is a crop that grows best when sown directly in the garden. In Delaware, the right time to direct sow is around Sunday, April 5, 2026, once soil temperatures are consistently warm enough for germination.

Because Delaware stretches across 3 USDA hardiness zones (7a, 7b, 8a), planting windows can shift by as much as two to four weeks from one end of the state to the other. Gardeners in the warmer southern zones can start earlier, while those in cooler northern zones should wait until the zone table above shows their last frost has passed.

With 60 days to maturity, Cosmos fits comfortably within Delaware's growing season in most zones. In the warmest parts of the state, a second planting later in the season may be possible.

Cosmos requires full sun (6-8 hours) and low-moderate moisture. Most of Delaware receives adequate sunlight during the growing season, though gardeners in humid eastern regions should watch for fungal issues and ensure good air circulation.

For the most precise planting dates tailored to your exact location, enter your ZIP code on our planting calendar or use the zone table above to find the schedule for your area of Delaware.

Frequently Asked Questions

When should I plant Cosmos in Delaware?

In Delaware, direct sow Cosmos outdoors around Sunday, April 5, 2026. Delaware spans zones 7a–8a, so gardeners in warmer zones can plant earlier.

What is the last frost date in Delaware?

Delaware spans 3 USDA zones (7a, 7b, 8a), so last frost dates vary by region. Hockessin, Saint Georges, Yorklyn (7a) sees frost until around Friday, April 10, 2026, while Bethany Beach, Fenwick Island, Ocean View (8a) is frost-free much earlier.

How long does Cosmos take to grow in Delaware?

Cosmos takes about 60 days from transplant (or direct sow) to harvest. In Delaware's longer-season zones, a second planting in late summer may be possible.

What USDA zones does Delaware cover for Cosmos?

Delaware includes zones 7a, 7b, 8a. Cosmos grows well across all of these zones with adjusted timing — use the zone table above to find the right dates for your part of the state.

Find Precise Dates for Your City

Select a city for exact planting dates based on local frost records.

Bear 7b Bethany Beach 8a Bethel 7b Bridgeville 7b Camden Wyoming 7b Cheswold 7b Claymont 7b Clayton 7b Dagsboro 7b Delaware City 7b Delmar 7b Dover 7b Dover Afb 7b Ellendale 7b Felton 7b Fenwick Island 8a Frankford 7b Frederica 7b Georgetown 7b Greenwood 7b Harbeson 7b Harrington 7b Hartly 7b Hockessin 7a Houston 7b Kenton 7b Kirkwood 7b Laurel 7b Lewes 7b Lincoln 7b Little Creek 7b Magnolia 7b Marydel 7b Middletown 7b Milford 7b Millsboro 7b Millville 7b Milton 7b Montchanin 7b Nassau 7b New Castle 7b Newark 7b Ocean View 8a Odessa 7b Port Penn 7b Rehoboth Beach 8a Rockland 7b Saint Georges 7a Seaford 7b Selbyville 7b Smyrna 7b Townsend 7b Viola 7b Wilmington 7b Winterthur 7b Woodside 7a Yorklyn 7a

Other Plants for Delaware

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 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

When to Plant Cosmos in Other States

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