When to Plant Leek in Claremont, Illinois (62421)

Location

Claremont, Illinois

ZIP Code

62421

USDA Zone

Last Frost

Wednesday, April 15, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Wednesday, February 4, 2026

Transplant Outdoors

Wednesday, April 29, 2026

Based on last frost Wednesday, April 15, 2026 · Zone 6b

Pro tip: Start Leek seeds indoors 10 weeks before your last frost date, then transplant outdoors around Wednesday, April 29, 2026.

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🌿 Plant Details

Scientific Name Allium ampeloprasum

Days to Maturity 120 days

☀️ Growing Requirements

☀️

Sun

Full Sun

💧

Water

Regular

Seeds typically germinate in 1-7 days

Ready to Plant Leek in Claremont?

Get your seeds now so they're ready by Wednesday, February 4, 2026.

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🤝 Good Companions

CeleryAppleCarrot

⚠️ Avoid Planting Near

Swiss Chard

🤝

Full Companion Planting Guide for Leek

See which plants help Leek 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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🌾 Seed Saving Guide

🟡 Moderate

✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Biennial — allow flowering in year 2. Harvest seed heads when seeds are black and ripe.

Processing

Cut seed heads into bags when most seeds are black, dry 1 week, thresh gently.

Seed Viability

Up to 2 years when stored cool, dark, and dry.

Pro Tip

Leeks cross-pollinate with onions via insects. Isolate by at least a mile for truly pure seed.

Frequently Asked Questions

When should I plant Leek in Claremont, Illinois? +

In Claremont (Zone 6b), start Leek seeds indoors around Wednesday, February 4, 2026 and transplant outdoors around Wednesday, April 29, 2026.

What is the last frost date for Claremont, Illinois? +

The average last spring frost date for Claremont, Illinois (ZIP 62421) is around Wednesday, April 15, 2026. This is based on NOAA climate normals for USDA Zone 6b.

How long does Leek take to grow? +

Leek typically matures in about 120 days from transplanting. In Claremont, that means you can expect harvest around Wednesday, April 29, 2026 plus 120 days.

Should I start Leek indoors or direct sow in Illinois? +

Leek should be started indoors 10 weeks before your last frost date. In Claremont, that means starting around Wednesday, February 4, 2026.

📚 More Leek Planting Guides

🗺️

Leek in Illinois

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 6b Leek Guide

All cities in your zone · Avg dates

→

Other Plants for Claremont

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 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 Leek in Zone 6b

Leek (Allium ampeloprasum) is a popular garden vegetable. In Claremont, Illinois, which is in USDA Hardiness Zone 6b, you should start seeds indoors around Wednesday, February 4, 2026.

Your average last frost date is Wednesday, April 15, 2026. Plan to transplant your Leek seedlings outdoors around Wednesday, April 29, 2026, about 2 weeks after your last frost date.