How to Grow Japanese Giant Radish Sakurajima
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Japanese Giant Radish Sakurajima
Raphanus sativus var. gigantis
vegetableSakurajima is a legendary Japanese heirloom radish variety known for producing enormous, mild-flavored roots that can weigh 20-50 pounds or more in ideal conditions. Despite their gigantic size, these radishes remain tender, crisp, and surprisingly sweet with minimal pungency. This dramatic variety has been cultivated in Japan for centuries and is prized for its culinary versatility and impressive garden presence.
When should you plant Japanese Giant Radish Sakurajima in your zone?
Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.
Example Japanese Giant Radish Sakurajima timeline · Pittsburgh, PA (Zone 6b)
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Plant Japanese Giant Radish Sakurajima
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Japanese Giant Radish Sakurajima
Around Jun 16≈ 60 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Japanese Giant Radish Sakurajima dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Zones 4-8 are ideal; can grow in cooler zones as a fall/winter crop, and in warmer zones as a cool-season vegetable
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Get my Japanese Giant Radish Sakurajima timeline →Growth Stages
Germination & Seedling
2-3 weeksSeeds sprout in 3-7 days. True leaves emerge, and seedlings develop their first set of feathery foliage.
Keep soil consistently moist. Thin seedlings early to proper spacing to reduce competition. Provide bright light to prevent leggy growth. Protect from slugs and flea beetles.
Vegetative Growth
3-4 weeksPlant develops a rosette of deeply lobed leaves. Root begins to swell underground but remains unharvestable. Foliage reaches 12-18 inches tall.
Maintain consistent watering and even soil moisture. Remove competing weeds. Apply balanced fertilizer every 2-3 weeks. Mulch around plants to retain moisture and regulate soil temperature.
Root Expansion
4-6 weeksRoot rapidly enlarges underground, becoming visible at soil surface. Radish takes on its characteristic round or elongated shape. Foliage begins to yellow slightly as resources shift to root development.
Continue deep, consistent watering—this stage is critical for size. Do not let soil dry out. Reduce nitrogen fertilizer and switch to potassium-rich formula to encourage root growth rather than foliage. Clear away any soil covering the radish crown to allow proper expansion.
Maturity & Harvest Readiness
2-4 weeksRoot reaches 6-12+ inches diameter and significant weight. The crown becomes visible above soil. Foliage may show signs of stress or yellowing as the plant channels all energy to the root.
Maintain steady moisture through final weeks. Do not fertilize heavily at this stage. Check root size by gently uncovering the crown. Harvest when desired size is reached—the plant will not improve further in flavor after this point.
Post-Harvest & Storage
VariableHarvested roots are cleaned and can be stored for weeks to months in cool conditions. Cut foliage can be composted or used as green manure.
Harvest by loosening soil around the plant and pulling gently. Remove foliage immediately. Store in cool (32-40°F), humid (90-95% RH) environment. Leave soil slightly damp but not wet to prevent dehydration.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Row covers on young plants; neem oil or insecticidal soap; remove crop residue; attract beneficial insects with flowers.
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Row covers; collars around transplant stems; diatomaceous earth around base; crop rotation.
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and
Hand-pick in early morning or evening; beer traps; copper tape barriers; encourage ground beetles and parasitic wasps; diatomaceous earth.
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Row covers; hand-pick clusters of eggs (red and white); neem oil; remove crop debris.
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Crop rotation (avoid replanting in same soil for 3+ years); solarization; resistant varieties; amend with beneficial fungi and bacteria.
Uses
Roasted or Braised Root Vegetable
CulinarySakurajima radishes become sweet, mild, and tender when cooked. They can be roasted, braised, stir-fried, or steamed like turnips. Their large size makes them ideal for hearty dishes and bulk cooking. [source]
Fresh Salads and Slaws
CulinaryThinly sliced raw Sakurajima radishes provide crisp, refreshing texture and mild, slightly sweet flavor. Use in salads, coleslaws, or as a crunchy garnish. [source]
Greens for Cooking and Salads
CulinaryThe young radish leaves are edible with a peppery, mineral flavor similar to mustard greens. Use in salads, sautéed as a side dish, or added to soups. [source]
Digestive and Immune Support
MedicinalRadishes contain glucosinolates and vitamin C, traditionally used to support digestion and immune function in Japanese and traditional Asian medicine. [source]
Extended Season Storage Crop
HouseholdSakurajima radishes are excellent for fall and winter gardening in cool climates, providing a long-season, cold-hardy root vegetable that stores well for months in cool conditions. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Harvest when the root reaches desired size by gently loosening soil around the plant with a garden fork and pulling firmly. Sakurajima radishes can be harvested small (4-6 inches, 60 days) for tender eating or allowed to grow large (12+ inches, 100+ days) for impressive presentation. Foliage can be harvested for cooking once the root is established. For storage, remove greens immediately, brush off excess soil, and refrigerate at 32-40°F; they will keep 2-4 months. Spring planting produces smaller roots; fall/winter planting in mild climates yields larger specimens due to extended cool growing season.
Fun Facts
- 🌱 The Sakurajima variety originated in the Sakurajima region near Kagoshima, Japan, where it has been cultivated for over 400 years; the record for the largest Sakurajima radish is over 100 pounds, grown in Japan.
- 🌱 Despite weighing up to 50 pounds, Sakurajima radishes remain remarkably mild and sweet compared to smaller radish varieties, lacking the sharp bite typically associated with radishes.
- 🌱 In Japan, these giant radishes are traditionally displayed at harvest festivals and farmers markets as a sign of agricultural pride and abundance; they are also pickled whole or sliced for extended storage and consumption throughout winter.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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