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How to Grow Watermelon Radish

Reviewed by MyLocalPlanting Editorial Team Updated Sources
Watermelon Radish (Raphanus sativus)

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🛠️ Supplies You'll Need

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🌿 Plant Overview

Scientific Name Raphanus sativus
Category vegetable
Days to Maturity 60 days
Starting Method Direct Sow

☀️ Growing Requirements

☀️

Sun

Full Sun (6-8 hours)

💧

Water

Regular (1-2 inches/week)

↔️

Spacing

4" apart

🌱

Depth

0.5" deep

📏

Height

6-10"

🌱

Germination

3-7 days

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🌾 Seed Saving Guide

🟢 Easy
✅ Open-pollinated — seeds grow true to parent

When to Harvest Seed

Allow plants to bolt and seed pods to fully dry and turn tan on the stalk.

Processing

Thresh dried pods, winnow to remove chaff, dry seeds 1 week before storing.

Seed Viability

Up to 5 years when stored cool, dark, and dry.

Pro Tip

Will cross with other radish varieties — isolate by 1000 feet to maintain the distinctive interior color.

Seed Storage Supplies

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Raised Bed Planting Guides

A 4×8 bed fits 9 per sq ft of Watermelon Radish. See plant counts, spacing grids, and companion pairings for every bed size →

Watermelon Radish Planting Calendar by Zone

Watermelon Radish Planting Calendar by State

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Frequently Asked Questions

When should I plant Watermelon Radish? +

Sow Watermelon Radish seeds directly in the garden 4 weeks before your last frost date. Use the search on this page to find exact dates for your location.

How long does Watermelon Radish take to grow? +

Watermelon Radish typically matures in about 60 days from planting. Exact timing varies by variety, soil conditions, and local climate.

Should I start Watermelon Radish indoors or direct sow? +

Watermelon Radish does best when direct sown outdoors. Plant seeds directly in the garden at the appropriate time based on your local frost dates.

How much sun does Watermelon Radish need? +

Watermelon Radish requires full sun (6-8 hours) to thrive.

How far apart should I plant Watermelon Radish? +

Space Watermelon Radish plants 4 inches apart to allow adequate airflow and root development.

How much water does Watermelon Radish need? +

Watermelon Radish has regular (1-2 inches/week) water needs. Consistent moisture is important especially during germination and early growth.

Can you save seeds from Watermelon Radish? +

Yes — seed saving difficulty for Watermelon Radish is rated easy. Allow plants to bolt and seed pods to fully dry and turn tan on the stalk. Thresh dried pods, winnow to remove chaff, dry seeds 1 week before storing.

How long do Watermelon Radish seeds last in storage? +

Properly dried and stored Watermelon Radish seeds remain viable for up to 5 years. Store in a cool, dark, dry location in an airtight container with a silica gel packet for best results.

Are Watermelon Radish seeds open-pollinated? +

Yes — Watermelon Radish is open-pollinated, meaning seeds saved from your harvest will grow plants true to the parent variety. This makes it an excellent candidate for building a self-sustaining garden.

About Watermelon Radish

Stunning daikon-type radish with white exterior and vivid pink-red interior. Mild and sweet. Best grown in cool weather (spring or fall). A social media favorite.

Expect your Watermelon Radish to be ready for harvest in approximately 60 days from planting.

Use the search above or browse by zone or state to find the perfect planting dates for your location.