Mustard greens

1. 1

   Pick variety by heat level and use

   Red Giant: large burgundy-red savoyed leaves, very hot wasabi-like flavour, the showy choice. Strong enough that even cooked it retains a kick. Looks dramatic in ornamental kitchen gardens. Green-in-Snow: very hardy, mid-green leaves, mild-to-medium peppery flavour — the choice for cooking and for milder eaters. Survives harder winters under cover. Wasabi mustard: intensely hot, more punchy than Red Giant, mostly used as a condiment or in sushi. Golden Frills: feathery yellow-green leaves, mild — closer to mizuna in style. For a first crop: Red Giant for visual drama and proper mustard heat.

2. 2

   Sow direct, March to October

   Cool-season crop. Spring sowings (March–May) crop until June bolt. Autumn sowings (August–October) crop into winter, especially under cover. Skip the hot midsummer (June–early August) — mustard greens bolt immediately in heat. Sow in shallow drills 1 cm deep, 25 cm between rows. Germination in 5–10 days at 15°C.

3. 3

   Thin to spacing matching use

   For cut-and-come-again salads: thin to 5 cm. For full mature plants (for stir-fries or pickling): thin to 25–30 cm. Mature plants reach 30–40 cm tall and can mass-crop in autumn — a single Red Giant plant produces a bowlful of leaves at maturity.

4. 4

   Sow under cover in September for winter cropping

   The most useful UK growing window. A September sowing under a cloche, low polytunnel, or cold frame establishes before frosts and crops from October through to March. Green-in-Snow is the variety bred specifically for this — the name reflects its winter hardiness. Outdoor September sowings crop until first hard frost, then survive but stop growing until spring.

5. 5

   Pick young for salads, older for cooking

   Young leaves (10–15 cm) have a mild peppery flavour suitable for mixed salads in small quantities — mustard greens are too hot on their own for most fresh salads. Mature leaves (20–30 cm) are too hot raw but cook beautifully — stir-fried, braised, in noodle soups, in dumplings. Cooking reduces the heat dramatically; even very hot raw leaves cook down to a milder kick.

6. 6

   Watch for flea beetle, slugs, and cabbage white

   Flea beetle: pinprick shot-hole damage in summer; cover with fine mesh or sow under cover. Slugs: love mustard greens like all brassicas; apply wool pellets and nematodes. Cabbage white butterfly: caterpillars on summer plants; cover with insect mesh from sowing in April–August. The pest problems are the main reason autumn–winter undercover is the safest mustard-green growing window.

7. 7

   Cook them, don't just salad them

   The biggest mustard-greens insight for UK home cooks. Raw, the leaves are too hot for most fresh salads (just a few finely sliced young leaves in a mixed bowl). Cooked, they're transformed: stir-fry with garlic and ginger for 2 minutes; add to ramen and noodle soups; braise with chilli and soy; pickle young leaves Korean-style. The classic Indian dish saag uses mustard greens (sarson ka saag) — far more authentic than spinach.

8. 8

   Save seed for mustard condiment

   Let one plant flower and set seed (yellow umbel flowers, then seed pods). Harvest seed pods as they brown but before they shatter (August onwards), hang upside-down in paper bags for 2 weeks, sieve out seed. Make English mustard: grind seeds, mix with water, leave 10 minutes for the enzymes to activate, season. Make brown mustard: similar but uses the brown seeds without grinding finely.

Flea beetle and caterpillars can be issues; fast-growing so often harvested before damage.