🥬 Komatsuna

Komatsuna, or Japanese mustard spinach, is a fast, vigorous leaf crop with glossy green leaves and a mild, spinach-like flavour with a gentle mustard edge. It tolerates both heat and cold, and bolts much less than spinach.

It is one of the easiest leaf crops to grow, giving repeated cuts over months. Use it as a baby leaf, or let plants grow to full size for cooking.

Varieties to try

Komatsuna (standard)Torasan (very vigorous, heat-tolerant)Summerfest (bolt-resistant)Savanna (tender)

Sow from March to September, 1 cm deep, in rows 20–30 cm apart, or scatter thickly. Thin to 15–20 cm for full-sized plants, or leave closer for baby leaf. Seeds germinate in a few days.

In a polytunnel or under a cloche, komatsuna can be sown in autumn for winter leaves. Fine mesh at sowing helps keep flea beetle off. Sow successionally every 2–3 weeks.

Top tips

• Sow from spring to early autumn.
• Use fine mesh.
• Sow every 2–3 weeks.
• Thin for full plants.

Keep the soil moist and weed-free. It will bolt in drought, so water in dry spells. Feed lightly if growth is slow.

Flea beetle, slugs and aphids can be problems, and caterpillars may attack in summer. Cover with fine mesh. Rotate with other brassicas.

Komatsuna is a quick, forgiving crop. A fortnightly sowing keeps the table supplied. For tender leaves, grow it quickly with plenty of water and avoid letting it get too stressed. The plants recover well from cutting, giving three or four harvests before they flower.

Top tips

• Water in dry spells.
• Use fine mesh.
• Feed lightly.
• Rotate with other brassicas.

Watch out for

Flea beetleSlugsCaterpillarsAphids

Cut baby leaves at 10–15 cm, from three to four weeks, or whole plants at 6–8 weeks. Cut 2.5 cm above the base for regrowth, up to three times. Pick outer leaves for a longer harvest.

Harvest before the flower stalks appear. The flower buds are edible like broccoli raab.

Top tips

• Cut above the base for regrowth.
• Pick before flowering.
• Eat the flower buds.
• Harvest in the morning.

Cook komatsuna as you would spinach: stir-fry, steam, or add to soups, noodles, curries and omelettes. Young leaves are good raw in salads. It requires no special preparation, and stems cook as fast as leaves.

Keeps for 3–4 days in the fridge. Blanch for 1 minute and freeze in portions for winter cooking.

Komatsuna doesn't turn bitter or stringy, and the thick, juicy stems are as good as the leaves. Try it in a miso soup, with garlic and soy sauce in a stir-fry, or lightly steamed with sesame oil. The flowers in spring are lovely in salads.

Top tips

• Cook stems and leaves together.
• Use young leaves raw.
• Blanch and freeze.
• Stir-fry with garlic.