When to Plant Celery in Denver, Colorado (80262)

Location

Denver, Colorado

ZIP Code

80262

USDA Zone

Last Frost

Monday, April 20, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Monday, February 9, 2026

Transplant Outdoors

Monday, May 4, 2026

Based on last frost Monday, April 20, 2026 · Zone 6a

Pro tip: Start Celery seeds indoors 10 weeks before your last frost date, then transplant outdoors around Monday, May 4, 2026.

🌿 Plant Details

Scientific Name Apium graveolens

Days to Maturity 130 days

☀️ Growing Requirements

☀️

Sun

Full Sun

💧

Water

Regular

Seeds typically germinate in 8-28 days

Ready to Plant Celery in Denver?

Get your seeds now so they're ready by Monday, February 9, 2026.

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🤝 Good Companions

CosmosDaisySnapDragon

⚠️ Avoid Planting Near

CornAster

🤝

Full Companion Planting Guide for Celery

See which plants help Celery 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

🔴 Difficult

✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Celery is biennial — it seeds in year 2. Harvest umbels just before seeds shatter in summer.

Processing

Cut seed heads into bags, dry 2 weeks, thresh to release seeds.

Seed Viability

Up to 3 years when stored cool, dark, and dry.

Pro Tip

In cold climates, dig celery in fall, store roots in a root cellar, and replant in spring for year-2 flowering.

Frequently Asked Questions

When should I plant Celery in Denver, Colorado? +

In Denver (Zone 6a), start Celery seeds indoors around Monday, February 9, 2026 and transplant outdoors around Monday, May 4, 2026.

What is the last frost date for Denver, Colorado? +

The average last spring frost date for Denver, Colorado (ZIP 80262) is around Monday, April 20, 2026. This is based on NOAA climate normals for USDA Zone 6a.

How long does Celery take to grow? +

Celery typically matures in about 130 days from transplanting. In Denver, that means you can expect harvest around Monday, May 4, 2026 plus 130 days.

Should I start Celery indoors or direct sow in Colorado? +

Celery should be started indoors 10 weeks before your last frost date. In Denver, that means starting around Monday, February 9, 2026.

📚 More Celery Planting Guides

🗺️

Celery in Colorado

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 6a Celery Guide

All cities in your zone · Avg dates

→

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Growing Celery in Zone 6a

Celery (Apium graveolens) is a popular garden vegetable. In Denver, Colorado, which is in USDA Hardiness Zone 6a, you should start seeds indoors around Monday, February 9, 2026.

Your average last frost date is Monday, April 20, 2026. Plan to transplant your Celery seedlings outdoors around Monday, May 4, 2026, about 2 weeks after your last frost date.