When to Plant Echinacea (Coneflower) in Honolulu, Hawaii (96821)

Location

Honolulu, Hawaii

ZIP Code

96821

USDA Zone

12b

Last Frost

Thursday, January 1, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Thursday, October 23, 2025

Transplant Outdoors

Thursday, January 15, 2026

Based on last frost Thursday, January 1, 2026 · Zone 12b

Pro tip: Start Echinacea (Coneflower) seeds indoors 10 weeks before your last frost date, then transplant outdoors around Thursday, January 15, 2026.

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🌿 Plant Details

Scientific Name Echinacea purpurea

Days to Maturity 365 days

Mature Height 24-48"

Spread 24"

Type Perennial

☀️ Growing Requirements

☀️

Sun

Full Sun to Partial Shade

💧

Water

Low (drought tolerant once established)

↔️

Spacing

18" apart

🌱

Planting Depth

0.25" deep

Seeds typically germinate in 14-21 days

Ready to Plant Echinacea (Coneflower) in Honolulu?

Get your seeds now so they're ready by Thursday, October 23, 2025.

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🤝 Good Companions

Black-eyed SusanLavenderSage

🤝

Full Companion Planting Guide for Echinacea (Coneflower)

See which plants help Echinacea (Coneflower) 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 seed heads to dry fully on the plant through fall. Leave for birds or harvest before winter.

Processing

Wear gloves — seed heads are spiky. Rub seeds out with gloved hands, spread to dry 1 week.

Seed Viability

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

Pro Tip

Cold-stratify seeds for 4–8 weeks to significantly improve germination rates.

🪴

Raised Bed Planting Guides

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

Frequently Asked Questions

When should I plant Echinacea (Coneflower) in Honolulu, Hawaii? +

In Honolulu (Zone 12b), start Echinacea (Coneflower) seeds indoors around Thursday, October 23, 2025 and transplant outdoors around Thursday, January 15, 2026.

What is the last frost date for Honolulu, Hawaii? +

The average last spring frost date for Honolulu, Hawaii (ZIP 96821) is around Thursday, January 1, 2026. This is based on NOAA climate normals for USDA Zone 12b.

How long does Echinacea (Coneflower) take to grow? +

Echinacea (Coneflower) typically matures in about 365 days from transplanting. In Honolulu, that means you can expect harvest around Thursday, January 15, 2026 plus 365 days.

Should I start Echinacea (Coneflower) indoors or direct sow in Hawaii? +

Echinacea (Coneflower) should be started indoors 10 weeks before your last frost date. In Honolulu, that means starting around Thursday, October 23, 2025.

📚 More Echinacea (Coneflower) Planting Guides

🗺️

Echinacea (Coneflower) in Hawaii

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 12b Echinacea (Coneflower) Guide

All cities in your zone · Avg dates

→

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Growing Echinacea (Coneflower) in Zone 12b

Echinacea (Coneflower) (Echinacea purpurea) is a popular garden vegetable. In Honolulu, Hawaii, which is in USDA Hardiness Zone 12b, you should start seeds indoors around Thursday, October 23, 2025.

Your average last frost date is Thursday, January 1, 2026. Plan to transplant your Echinacea (Coneflower) seedlings outdoors around Thursday, January 15, 2026, about 2 weeks after your last frost date.