When to Plant Leek in Ballwin, Missouri (63021)

Location

Ballwin, Missouri

ZIP Code

63021

USDA Zone

Last Frost

Friday, April 10, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Friday, January 30, 2026

Transplant Outdoors

Friday, April 24, 2026

Based on last frost Friday, April 10, 2026 · Zone 7a

Pro tip: Start Leek seeds indoors 10 weeks before your last frost date, then transplant outdoors around Friday, April 24, 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 Ballwin?

Get your seeds now so they're ready by Friday, January 30, 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 Ballwin, Missouri? +

In Ballwin (Zone 7a), start Leek seeds indoors around Friday, January 30, 2026 and transplant outdoors around Friday, April 24, 2026.

What is the last frost date for Ballwin, Missouri? +

The average last spring frost date for Ballwin, Missouri (ZIP 63021) is around Friday, April 10, 2026. This is based on NOAA climate normals for USDA Zone 7a.

How long does Leek take to grow? +

Leek typically matures in about 120 days from transplanting. In Ballwin, that means you can expect harvest around Friday, April 24, 2026 plus 120 days.

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

Leek should be started indoors 10 weeks before your last frost date. In Ballwin, that means starting around Friday, January 30, 2026.

📚 More Leek Planting Guides

🗺️

Leek in Missouri

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 7a Leek Guide

All cities in your zone · Avg dates

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Other Plants for Ballwin

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Growing Leek in Zone 7a

Leek (Allium ampeloprasum) is a popular garden vegetable. In Ballwin, Missouri, which is in USDA Hardiness Zone 7a, you should start seeds indoors around Friday, January 30, 2026.

Your average last frost date is Friday, April 10, 2026. Plan to transplant your Leek seedlings outdoors around Friday, April 24, 2026, about 2 weeks after your last frost date.