When to Plant Kohlrabi in Haiku, Hawaii (96708)

Location

Haiku, Hawaii

ZIP Code

96708

USDA Zone

12a

Last Frost

Thursday, January 1, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Thursday, December 4, 2025

Transplant Outdoors

Thursday, December 18, 2025

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

Pro tip: Start Kohlrabi seeds indoors 4 weeks before your last frost date, then transplant outdoors around Thursday, December 18, 2025.

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🌿 Plant Details

Scientific Name Brassica oleracea var. gongylodes

Days to Maturity 55 days

Mature Height 12-18"

Spread 8"

Type Bulb

Fruit Size Small-Medium (2-3 inch bulb)

☀️ Growing Requirements

☀️

Sun

Full Sun to Partial Shade

💧

Water

Regular (consistent moisture prevents cracking)

↔️

Spacing

6" apart

🌱

Planting Depth

0.5" deep

Seeds typically germinate in 4-7 days

Ready to Plant Kohlrabi in Haiku?

Get your seeds now so they're ready by Thursday, December 4, 2025.

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🤝 Good Companions

BeetOnionCucumberHerb

⚠️ Avoid Planting Near

TomatoPepperStrawberry

🤝

Full Companion Planting Guide for Kohlrabi

See which plants help Kohlrabi 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

Allow plants to bolt in year 2. Harvest seed pods just before they shatter.

Processing

Thresh dried seed stalks in a bag, separate seeds from chaff by winnowing.

Seed Viability

Up to 4 years when stored cool, dark, and dry.

Pro Tip

Brassica oleracea — crosses with broccoli, cabbage, kale, and Brussels sprouts. Isolate by 1000 feet for purity.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 4 per sq ft of Kohlrabi. See plant counts, spacing grids, and companion pairings for every bed size →

Frequently Asked Questions

When should I plant Kohlrabi in Haiku, Hawaii? +

In Haiku (Zone 12a), start Kohlrabi seeds indoors around Thursday, December 4, 2025 and transplant outdoors around Thursday, December 18, 2025.

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

The average last spring frost date for Haiku, Hawaii (ZIP 96708) is around Thursday, January 1, 2026. This is based on NOAA climate normals for USDA Zone 12a.

How long does Kohlrabi take to grow? +

Kohlrabi typically matures in about 55 days from transplanting. In Haiku, that means you can expect harvest around Thursday, December 18, 2025 plus 55 days.

Should I start Kohlrabi indoors or direct sow in Hawaii? +

Kohlrabi should be started indoors 4 weeks before your last frost date. In Haiku, that means starting around Thursday, December 4, 2025.

📚 More Kohlrabi Planting Guides

🗺️

Kohlrabi in Hawaii

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 12a Kohlrabi Guide

All cities in your zone · Avg dates

→

Other Plants for Haiku

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Growing Kohlrabi in Zone 12a

Kohlrabi (Brassica oleracea var. gongylodes) is a popular garden vegetable. In Haiku, Hawaii, which is in USDA Hardiness Zone 12a, you should start seeds indoors around Thursday, December 4, 2025.

Your average last frost date is Thursday, January 1, 2026. Plan to transplant your Kohlrabi seedlings outdoors around Thursday, December 18, 2025, about -2 weeks after your last frost date.