When to Plant Cauliflower in New Castle, Delaware (19721)

Location

New Castle, Delaware

ZIP Code

19721

USDA Zone

Last Frost

Sunday, April 5, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Sunday, February 22, 2026

Transplant Outdoors

Sunday, April 5, 2026

Based on last frost Sunday, April 5, 2026 · Zone 7b

Pro tip: Start Cauliflower seeds indoors 6 weeks before your last frost date, then transplant outdoors around Sunday, April 5, 2026.

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🌿 Plant Details

Scientific Name Brassica oleracea var. botrytis

Days to Maturity 75 days

Mature Height 18-24"

Spread 24"

Type Head

Fruit Size Medium (6-8 inch head)

☀️ Growing Requirements

☀️

Sun

Full Sun (6 hours)

💧

Water

Regular (1-1.5 inches/week)

↔️

Spacing

18" apart

🌱

Planting Depth

0.5" deep

Seeds typically germinate in 4-10 days

Ready to Plant Cauliflower in New Castle?

Get your seeds now so they're ready by Sunday, February 22, 2026.

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🤝 Good Companions

BeetCeleryBeanOnion

⚠️ Avoid Planting Near

StrawberryTomato

🤝

Full Companion Planting Guide for Cauliflower

See which plants help Cauliflower 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

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Common Cauliflower Varieties

Popular cultivars to look for at your local nursery or seed supplier.

Snowball Y Improved

white 68d

Classic white cauliflower with dense, tight curds; reliable and widely adapted.

Cheddar

colored 68d

Orange-headed variety with a mild, buttery flavor and high beta-carotene content.

Graffiti

colored 80d

Brilliant purple cauliflower that holds its color when roasted; slightly nutty flavor.

Romanesco

specialty 80d

Lime-green logarithmic spirals with a mild, nutty taste; equally vegetable and art piece.

🌾 Seed Saving Guide

🔴 Difficult

✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Allow head to bloom fully after the eating stage. Harvest seed pods when dry and tan.

Processing

Thresh dried seed stalks, winnow seeds from chaff.

Seed Viability

Up to 5 years when stored cool, dark, and dry.

Pro Tip

B. oleracea — crosses with all other oleracea cole crops. Very difficult to keep pure at home scale.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 14 plants of Cauliflower. See plant counts, spacing grids, and companion pairings for every bed size →

Frequently Asked Questions

When should I plant Cauliflower in New Castle, Delaware? +

In New Castle (Zone 7b), start Cauliflower seeds indoors around Sunday, February 22, 2026 and transplant outdoors around Sunday, April 5, 2026.

What is the last frost date for New Castle, Delaware? +

The average last spring frost date for New Castle, Delaware (ZIP 19721) is around Sunday, April 5, 2026. This is based on NOAA climate normals for USDA Zone 7b.

How long does Cauliflower take to grow? +

Cauliflower typically matures in about 75 days from transplanting. In New Castle, that means you can expect harvest around Sunday, April 5, 2026 plus 75 days.

Should I start Cauliflower indoors or direct sow in Delaware? +

Cauliflower should be started indoors 6 weeks before your last frost date. In New Castle, that means starting around Sunday, February 22, 2026.

📚 More Cauliflower Planting Guides

🗺️

Cauliflower in Delaware

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 7b Cauliflower Guide

All cities in your zone · Avg dates

→

Other Plants for New Castle

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 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) 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 Cauliflower in Zone 7b

Cauliflower (Brassica oleracea var. botrytis) is a popular garden vegetable. In New Castle, Delaware, which is in USDA Hardiness Zone 7b, you should start seeds indoors around Sunday, February 22, 2026.

Your average last frost date is Sunday, April 5, 2026. Plan to transplant your Cauliflower seedlings outdoors around Sunday, April 5, 2026, about 0 weeks after your last frost date.