How to grow mizuna
Overview
Mizuna is a cool-season Asian brassica grown for its deeply cut, peppery leaves used in salads and stir-fries. Unlike many brassicas, it is cut-and-come-again, producing tender regrowth after harvesting. Quick to mature, it thrives in mild weather and is ideal for gaps in the garden.
Varieties
- Mizuna 'Purple Delight' — Vibrant purple leaves add colour to salads and are slightly milder than green types.
- Mizuna 'Kyoto' — Standard green variety, very fast-growing and reliable in Australian gardens.
- Mizuna 'Early' — An early-maturing type suited for quick crops in cool conditions.
Soil Preparation
Mizuna prefers well-drained, fertile loam with a pH of 6.0–7.0. Enrich the bed with well-rotted compost or aged manure before planting. Avoid heavy clay soils; if drainage is poor, grow in raised beds or large pots.
Growing Guide
Sow seed directly into moist, weed-free soil at 6 mm depth, spacing rows 30 cm apart. Thin seedlings to 20–30 cm between plants for full-sized leaves. Mizuna prefers a sheltered spot with morning sun and afternoon shade, especially in warmer climates. Keep soil consistently moist but not waterlogged; mulch around the base to retain moisture and cool the roots. Succession sow every 3–4 weeks for a continuous supply.
Sowing
Direct sow seeds 6 mm deep, about 1 cm apart, then thin to 20–30 cm spacing. Germination takes 5–10 days at soil temperatures of 10–20°C. Sow in punnets for transplanting if desired; seedlings are ready at 3–4 weeks.
Care
Apply a balanced liquid fertiliser (e.g., seaweed or fish emulsion) every 2–3 weeks during active growth. Remove any yellowing or damaged outer leaves to improve air circulation and encourage fresh growth. No pruning is needed apart from regular harvesting.
Companion Planting
Mizuna grows well with lettuce, spring onions, carrots, radishes, and beetroot. Avoid planting near other brassicas like broccoli or cabbage to reduce shared pest pressure. Alliums such as garlic and chives help deter flea beetles.
Common Pests & Risks
Flea beetles create small round holes in leaves; control with fine insect mesh or diatomaceous earth. Aphids cluster on new growth — blast off with water or use insecticidal soap. Caterpillars (e.g., white butterfly) can be hand-picked or treated with Bacillus thuringiensis (Bt). Keep plants healthy with good airflow and avoid water stress.
Harvesting
Begin harvesting outer leaves when they reach 10–15 cm long, usually 6–8 weeks from sowing. For cut-and-come-again, snip leaves at the base, leaving the central crown to regrow. Whole plants can be harvested at once by cutting just above the soil line.
In the Kitchen
Use fresh mizuna leaves in salads for a mild, peppery bite, or lightly stir-fry with garlic and oyster sauce. Young leaves are tender; older leaves can be wilted into soups. Store in a plastic bag in the fridge for up to a week.
Troubleshooting
Yellowing leaves: often caused by overwatering or nitrogen deficiency — improve drainage and feed with liquid fertiliser. Holes in leaves: flea beetle damage — cover with insect mesh early. Plants bolting to seed: triggered by heat or long days — provide afternoon shade and sow in cooler months. Stunted growth: compacted soil or root competition — grow in well-loosened beds and thin seedlings properly. Leggy seedlings: insufficient light — transplant to a sunnier spot once established.