When to Plant Serrano Pepper in Honolulu, Hawaii (96817)

Location

Honolulu, Hawaii

ZIP Code

96817

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 Serrano Pepper 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 Capsicum annuum

Days to Maturity 80 days

Mature Height 24-36"

Spread 18"

Type Bush

Fruit Size Small (1-2 inches)

☀️ Growing Requirements

☀️

Sun

Full Sun (6-8 hours)

💧

Water

Moderate

↔️

Spacing

18" apart

🌱

Planting Depth

0.25" deep

Seeds typically germinate in 7-14 days

Ready to Plant Serrano Pepper in Honolulu?

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

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🤝 Good Companions

BasilCarrotTomato

⚠️ Avoid Planting Near

Fennel

🤝

Full Companion Planting Guide for Serrano Pepper

See which plants help Serrano Pepper 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

Allow peppers to fully ripen red on the plant.

Processing

Remove seeds carefully — serrano is quite hot. Dry flat for 1–2 weeks. Gloves recommended.

Seed Viability

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

Pro Tip

C. annuum — crosses freely with other annuum peppers. Isolate by 300 feet for pure seed.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 14 plants of Serrano Pepper. See plant counts, spacing grids, and companion pairings for every bed size →

Frequently Asked Questions

When should I plant Serrano Pepper in Honolulu, Hawaii? +

In Honolulu (Zone 12b), start Serrano Pepper 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 96817) is around Thursday, January 1, 2026. This is based on NOAA climate normals for USDA Zone 12b.

How long does Serrano Pepper take to grow? +

Serrano Pepper typically matures in about 80 days from transplanting. In Honolulu, that means you can expect harvest around Thursday, January 15, 2026 plus 80 days.

Should I start Serrano Pepper indoors or direct sow in Hawaii? +

Serrano Pepper should be started indoors 10 weeks before your last frost date. In Honolulu, that means starting around Thursday, October 23, 2025.

📚 More Serrano Pepper Planting Guides

🗺️

Serrano Pepper in Hawaii

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 12b Serrano Pepper Guide

All cities in your zone · Avg dates

→

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Growing Serrano Pepper in Zone 12b

Serrano Pepper (Capsicum annuum) 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 Serrano Pepper seedlings outdoors around Thursday, January 15, 2026, about 2 weeks after your last frost date.