When to Plant Kohlrabi in Saint Petersburg, Florida (33708)

Location

Saint Petersburg, Florida

ZIP Code

33708

USDA Zone

10b

Last Frost

Thursday, January 15, 2026

📅 Your 2026 Planting Dates

Start Seeds Indoors

Thursday, December 18, 2025

Transplant Outdoors

Thursday, January 1, 2026

Based on last frost Thursday, January 15, 2026 · Zone 10b

Pro tip: Start Kohlrabi seeds indoors 4 weeks before your last frost date, then transplant outdoors around Thursday, January 1, 2026.

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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 Saint Petersburg?

Get your seeds now so they're ready by Thursday, December 18, 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 Saint Petersburg, Florida? +

In Saint Petersburg (Zone 10b), start Kohlrabi seeds indoors around Thursday, December 18, 2025 and transplant outdoors around Thursday, January 1, 2026.

What is the last frost date for Saint Petersburg, Florida? +

The average last spring frost date for Saint Petersburg, Florida (ZIP 33708) is around Thursday, January 15, 2026. This is based on NOAA climate normals for USDA Zone 10b.

How long does Kohlrabi take to grow? +

Kohlrabi typically matures in about 55 days from transplanting. In Saint Petersburg, that means you can expect harvest around Thursday, January 1, 2026 plus 55 days.

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

Kohlrabi should be started indoors 4 weeks before your last frost date. In Saint Petersburg, that means starting around Thursday, December 18, 2025.

📚 More Kohlrabi Planting Guides

🗺️

Kohlrabi in Florida

Zone-by-zone breakdown · Full state guide

→ 🌡️

Zone 10b Kohlrabi Guide

All cities in your zone · Avg dates

→

Other Plants for Saint Petersburg

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Growing Kohlrabi in Zone 10b

Kohlrabi (Brassica oleracea var. gongylodes) is a popular garden vegetable. In Saint Petersburg, Florida, which is in USDA Hardiness Zone 10b, you should start seeds indoors around Thursday, December 18, 2025.

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