When to Plant Celosia in Arlington, Colorado (81021)

Location

Arlington, Colorado

ZIP Code

81021

USDA Zone

Last Frost

Saturday, April 25, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Saturday, March 14, 2026

Transplant Outdoors

Saturday, May 2, 2026

Based on last frost Saturday, April 25, 2026 · Zone 5b

Pro tip: Start Celosia seeds indoors 6 weeks before your last frost date, then transplant outdoors around Saturday, May 2, 2026.

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🌿 Plant Details

Scientific Name Celosia argentea

Days to Maturity 75 days

Mature Height 12-36"

Spread 9"

☀️ Growing Requirements

☀️

Sun

Full Sun (6-8 hours)

💧

Water

Moderate (1 inch/week)

↔️

Spacing

9" apart

🌱

Planting Depth

0.125" deep

Seeds typically germinate in 10-14 days

Ready to Plant Celosia in Arlington?

Get your seeds now so they're ready by Saturday, March 14, 2026.

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🤝 Good Companions

MarigoldZinniaBasil

🤝

Full Companion Planting Guide for Celosia

See which plants help Celosia thrive, which to keep away, and raised bed layout tips →

🛠️ Supplies You'll Need

🌱 Seed Starting Trays 🪴 Seed Starting Mix 💡 Grow Lights 🌡️ Heat Mat 🌍 Flower Garden Soil ✂️ Pruning Shears 🚿 Watering Can

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🌾 Seed Saving Guide

🟢 Easy

✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Allow plume or cockscomb heads to dry fully on the plant until fluffy or papery.

Processing

Rub dried heads gently between hands over a bowl to release tiny seeds. Dry 1 week.

Seed Viability

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

Pro Tip

Celosia self-sows readily in warm climates. Seeds are tiny — store in small labeled packets.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 56 plants of Celosia. See plant counts, spacing grids, and companion pairings for every bed size →

Frequently Asked Questions

When should I plant Celosia in Arlington, Colorado? +

In Arlington (Zone 5b), start Celosia seeds indoors around Saturday, March 14, 2026 and transplant outdoors around Saturday, May 2, 2026.

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

The average last spring frost date for Arlington, Colorado (ZIP 81021) is around Saturday, April 25, 2026. This is based on NOAA climate normals for USDA Zone 5b.

How long does Celosia take to grow? +

Celosia typically matures in about 75 days from transplanting. In Arlington, that means you can expect harvest around Saturday, May 2, 2026 plus 75 days.

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

Celosia should be started indoors 6 weeks before your last frost date. In Arlington, that means starting around Saturday, March 14, 2026.

📚 More Celosia Planting Guides

🗺️

Celosia in Colorado

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 5b Celosia Guide

All cities in your zone · Avg dates

→

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Growing Celosia in Zone 5b

Celosia (Celosia argentea) is a popular garden vegetable. In Arlington, Colorado, which is in USDA Hardiness Zone 5b, you should start seeds indoors around Saturday, March 14, 2026.

Your average last frost date is Saturday, April 25, 2026. Plan to transplant your Celosia seedlings outdoors around Saturday, May 2, 2026, about 1 weeks after your last frost date.