White Icicle Radish (Raphanus sativus) is a classic easy to grow heirloom variety dating back to the late 1800s, prized for its slender, snow-white roots and crisp, mild flavor. Often called the “summer daikon,” this fast-growing variety produces roots up to 5 inches long with a clean, refreshing bite that’s never overpowering. White Icicle thrives in cool to mild weather and matures quickly, making it an excellent choice for early spring or fall gardens. Its uniform roots, delicate texture, and old-fashioned flavor make it a favorite among home gardeners and chefs alike.
Common Names: White Icicle Radish, Long White Radish
Latin Name: Raphanus sativus
Type: Vegetable (Root Crop)
Life Cycle: Annual
USDA Zones: 2 - 11
Stratification: Not Required
Germination Ease: Easy
Sunlight: Full Sun to Partial Shade
Moisture: Moderate; prefers evenly moist soil
Soil: Loose, well-drained, sandy loam high in organic matter
Height: 8 - 12 inches (foliage)
Spread: 2 - 4 inches
Color: Pure white roots with green tops
Flavor Profile: Crisp and refreshing with a mild peppery bite; delicate texture and clean finish
Bloom Season: Grown for roots (blooms only when left to seed)
Companion Plants: Lettuce, carrots, peas, and spinach; avoid planting near cabbage or hyssop
Potential Toxicity: Non-Toxic
Climate Adaptability: Cool-season crop; performs best in spring and fall, tolerates mild summer heat
~ Sowing ~
When to Sow Outside:
Sow directly outdoors as soon as soil can be worked in early spring. For a continuous harvest, sow every two weeks until midsummer. In fall, sow again about 4–6 weeks before the first expected frost.
When to Start Inside:
Not recommended — radishes are best direct-sown.
Days to Emerge:
3 - 7 days
Seed Depth:
1/2 inch deep
Seed Spacing:
Sow seeds 1 inch apart in rows; thin to 2 inches apart for full-sized roots.
Row Spacing:
8 - 12 inches apart
Hardiness:
Frost-tolerant annual; best growth occurs in cool weather.
~ Growing ~
Soil:
Prefers loose, sandy, or loamy soil free of rocks or compaction to allow straight root development. Avoid nitrogen-heavy fertilizers that promote leafy growth over root formation.
Watering:
Keep soil evenly moist. Irregular watering can cause roots to become woody or split.
Light and Temperature:
Thrives in full sun but tolerates light shade. Optimal growing temperatures are between 50°F and 70°F.
Maintenance:
Minimal care required. Thin seedlings early to prevent crowding. Harvest promptly for best texture.
Container Friendly:
Yes, grows well in deep containers (at least 6 inches). Choose loose soil and avoid overcrowding.
~ Harvesting ~
When to Harvest:
Harvest when roots are 4–5 inches long and about 1/2 inch in diameter, typically 25–30 days after sowing.
How to Harvest:
Gently pull roots from the soil while tops are still fresh and green. Loosen compact soil if needed.
Drying and Storing:
Store harvested radishes in the refrigerator for up to two weeks. Remove tops before storing to prevent moisture loss.
Edible Use:
Enjoy raw for crisp, mild heat or slice thinly for salads, sandwiches, and garnishes. Excellent roasted, pickled, or added to stir-fries for a mild daikon-like flavor.
~ Seed Saving ~
Seed Collection:
Allow a few plants to bolt and flower. Once pods dry on the plant, cut and collect them for seed.
Seed Cleaning:
Break open pods and remove seeds; winnow off chaff.
Seed Storage:
Store in a cool, dry, dark place. Seeds remain viable for up to 5 years.
~ Additional Information ~
Forage for Pollinators:
When left to bloom, radish flowers attract bees, hoverflies, and beneficial pollinators.
Origin:
An heirloom variety popularized in Europe in the late 19th century; also known as “Long White Vienna” in older seed catalogs.
Nomenclature:
The name “Icicle” refers to its slender, snow-white roots resembling frozen drops of ice.
History:
White Icicle has been grown for over a century and remains valued for its crisp texture, mild flavor, and adaptability to both garden and container growing.
Potential Toxicity:
Non-toxic and safe for all culinary uses.
Climate Adaptability:
Grows best in cool, mild climates; can tolerate some heat but prefers consistent moisture and partial shade in warm regions.
