Variety field guide
What to expect from Osaka Shirona Seeds
Osaka Shirona pairs broad, bright green leaves with flat white stalks for a mild, crisp cabbage harvest.
Read the complete product descriptionTraits, flavor, garden use, variety notes, and the full catalog record
Osaka Shirona pairs broad, bright green leaves with flat white stalks for a mild, crisp cabbage harvest. Its loose growth makes it easy to gather young greens or cut a larger plant for soup, braising and stir-frying. Traditionally used in Japanese cooking, it is especially useful where a tender leafy cabbage is preferred. Small successive plantings supply fresh greens without requiring every plant to reach full size at once.
A mild, leafy cabbage for soups, salads and quick cooking.
Growing facts
- Botanical name: Brassica rapa
- Maturity or display: 40-60 days
- Mature size: Loose leafy rosette; size varies with harvest stage
- Spacing: 12 in between plants; rows 18 in
About the variety
Osaka Shirona belongs to the Japanese shirona group of leafy Brassica rapa vegetables. Supplier descriptions of a possible cabbage/pak choi cross are tentative, not a verified breeding pedigree. The packet uses the supported species name and avoids equating it with every komatsuna strain.
Starting seed
Sow 1/4-1/2 in. deep for mild spring weather or late-summer planting. Keep moist at 60-70 F; allow about 4-10 days to sprout. Thin to 12 in. apart, rows 18 in. apart. Use sun and fertile soil; prolonged cold or heat may trigger bolting.
Care through the season
Maintain even moisture and remove weeds while small. Rotate brassica beds and use insect netting before flea beetles or caterpillars arrive. Grow for a cool harvest; extended cold on young plants can induce flowering, and summer heat can reduce leaf quality. Fall sowings often avoid spring cold followed by heat.
Harvest and use
Pick tender outer leaves or cut plants above the soil at a useful size, about 40-60 days from sowing. Refrigerate; loose leaves are best used soon. Save seed from several healthy plants isolated from other flowering Brassica rapa; dry mature pods before threshing.
Saving seed
These open-pollinated brassicas are insect-pollinated. Keep several healthy, typical plants for seed and prevent crossing with other flowering varieties of the same species. Some plants need a cold period before flowering. Let pods mature, then cut and dry them under cover before they shatter; clean, label and store seed cool and dry.
Common problems
Check young leaves for flea beetle holes, aphids and caterpillars. Use row covers early, inspect regularly, and remove badly diseased plants. Crop rotation, drainage and steady watering help limit root disease and stress. A flowering stem means the leafy harvest is ending; use the leaves promptly.
Frequently asked questions
Does it form a tight head?
Osaka Shirona pairs broad, bright green leaves with flat white stalks for a mild, crisp cabbage harvest.
When should I harvest?
Pick tender outer leaves or cut plants above the soil at a useful size, about 40-60 days from sowing. Refrigerate; loose leaves are best used soon. Save seed from several healthy plants isolated from other flowering Brassica rapa; dry mature pods before threshing.
Why is it flowering early?
Maintain even moisture and remove weeds while small. Rotate brassica beds and use insect netting before flea beetles or caterpillars arrive. Grow for a cool harvest; extended cold on young plants can induce flowering, and summer heat can reduce leaf quality. Fall sowings often avoid spring cold followed by heat.
