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Watermelon Radish Seeds

Watermelon Radish Seeds

San Diego Seed Company

Regular price $3.95 USD
Regular price Sale price $3.95 USD
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Product Details

Product Information

Watermelon radish is an heirloom variety radish. It produces a wonderful pink starburst center that adds a pop of color to any dish with a mild peppery flavor that is superb. It’s our most popular radish variety! Excellent for pickling, fermenting, and fresh eating—slice thinly for gorgeous salads!

Product Details

Approx Seed Count


Seed Weight

2G, .07oz

Botanical Name

Raphanus sativus

Planting Season 


Soil Temp

45° F+, 7°C+

Planting Depth

¼”, .6cm

Area to Sow

30' row, 9.1m row

Days to Germ.


Days to Maturity


Best Planting Method


Thin to

≥2" apart, 5cm apart

Final Spacing

≥4" apart, 10.2cm apart


7 days

Plant Spread

3", 7.6cm

Plant Height

4-6", 10cm-15cm


Planting by Zones

Zones 9-10

  • Radishes are a cool season crop in Zones 9 and 10. You can plant them in the fall through late spring. In mild areas they can be grown year round with crop protection.

Zones 2-8

  • Direct sow seeds when the threat of frost has passed and soil can be worked in early spring.

Planting Radish Seeds

  • In Zones 9 and 10, direct seed in full sun or transplant out. Because of our hot fall weather, we often plant radishes in starter trays to protect them from the heat and Santa Ana winds. We transplant them out in deeply irrigated soil under the protection of shade cloth.
  • To direct sow, plant seeds in well-worked soil that has been deeply watered and is debris free. Cover with 1/2″ (1.3cm) of finely sifted soil.
  • If you are using starter pots, plant seeds into thoroughly moist high-quality seed starting soil. Place seeds on the top of the soil and cover with 1/2″ (1.3cm) of finely sifted soil.
  • Once your radish seeds have germinated and are 1-2″ (2.5-5cm) tall, fertilize with an organic liquid fertilizer. When the plants are 3-4″ (7.6-10cm) tall you can plant them out into the garden.
  • Space plants at least 4″ (10cm) apart.

Growing Radishes

  • Radishes are easy to grow when grown in cool environments. Radishes do not respond well in hot, dry soils; they can become pithy and bitter.
  • Mulching heavily around your plants will help with weed suppression and moisture retention.

Harvesting Radishes

  • Radishes can be pulled from the ground at their desirable size. Do not let radishes get too big as they will become fibrous.

Growing Radishes in Containers

  • Radishes are great for growing in containers. Just make sure your container is at least 10″ (25.4cm) deep and wide enough to give each plant space to grow. Keep in mind containers will dry out faster because they have more surface area and less soil to hold onto moisture. Mulch heavily on the top layer of soil in the pot to keep the soil from drying out or heating up too much.

Southern California Pro Tips

  • Protecting radishes from heat spells or hot weather is critical. Use shade cloth when necessary.
  • Mulch heavily around your plants to ensure the soil does not dry out or heat up.
  • When planting in the fall, aphids can be an issue due to the heat. Watch your plants carefully and rinse off any aphids you see until the soil cools.

Companion Flowers/Crops

  • Radishes are a quick crop and can be grown easily in between other cool-season crops that take longer to mature. Broccolicabbage, and cauliflower are good choices.


Additional Learning Resources

  • New to starting crops from seeds? Please read our article, Starting Seeds Indoors to learn the basics!
  • We have an in-depth guide on growing radishes to provide additional tips and pest/disease management help!
  • More information about Integrated Pest Management strategies for aphids are available on our blog.
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