Pak Choi

Pak choi, also called bok choy, is a fast-growing oriental brassica that forms a tight upright rosette. Mature plants reach about 30–45cm tall and carry broad white or pale-green succulent stems beneath large green, lime or purple leaves. The crisp stalks and leaves are best lightly steamed, sautéed or stir-fried, while young foliage makes a tender salad crop.

It can be harvested as cut-and-come-again baby leaves in as little as four weeks, or grown for semi-mature and full heads over eight to ten weeks. Pak choi prefers the mild, damp conditions of spring and late summer into autumn. Heat, drought and cold checks can all trigger premature flowering, so sow small batches often and avoid relying on one midsummer crop.

Choose compact varieties for containers, bolt-resistant selections for summer heads, and coloured forms for decorative leaves. Most types can supply both baby leaves and mature rosettes.

Recommended varieties

Pak choi ‘Summer Breeze’ AGM

Bolt-resistant with good tolerance of heat and cold. Harvest as salad leaves or allow it to form succulent stalks and young summer heads.

Cultivar sourceAllotment Pro variety guide

Pak choi ‘Choko F1’ AGM

A mild-flavoured F1 hybrid with crisp stems and tolerance of warmer weather, making it useful for summer growing.

Cultivar sourceAllotment Pro variety guide

Pak choi ‘Glacier’ AGM

A British-bred F1 hybrid selected for British weather, with cold tolerance and resistance to bolting in hot conditions.

Cultivar sourceAllotment Pro variety guide

Pak choi ‘Ivory’

Crisp tasty white stems support dark-green fleshy leaves. Use baby foliage in salads and mature heads in stir-fries.

Cultivar sourceAllotment Pro variety guide

Pak choi ‘Red Choi’ AGM

An eye-catching cultivar with purple-red upper leaf surfaces, green undersides and bright-green stems. It is decorative as well as edible. ## 3 - Preparing The Ground Choose fertile soil that holds moisture without becoming waterlogged. Dig in about two bucketfuls of garden compost or well-rotted manure per square metre. Remove weeds, rake the surface to a fine texture and take out large stones. In a no-dig bed, apply organic matter as a surface mulch and sow or plant through it. Use full sun for early and late crops. For summer sowings, a cooler position with light shade reduces heat stress and slows bolting. Avoid sites where brassicas have grown recently if persistent soil-borne problems are present. ## 4 - Sowing Seeds germinate in about a week. Sow small batches every few weeks rather than a large single row, matching spacing to the intended harvest.

Cultivar sourceAllotment Pro variety guide

Choose fertile soil that holds moisture without becoming waterlogged. Dig in about two bucketfuls of garden compost or well-rotted manure per square metre. Remove weeds, rake the surface to a fine texture and take out large stones. In a no-dig bed, apply organic matter as a surface mulch and sow or plant through it.

Use full sun for early and late crops. For summer sowings, a cooler position with light shade reduces heat stress and slows bolting. Avoid sites where brassicas have grown recently if persistent soil-borne problems are present.

Seeds germinate in about a week. Sow small batches every few weeks rather than a large single row, matching spacing to the intended harvest.

Harden module-grown or purchased plug plants carefully, then plant outdoors from late spring once they are at least 10cm tall. Move the intact root ball without teasing roots apart. A check at transplanting may promote bolting.

Plant about 8cm apart for baby leaves, 20cm for intermediate heads and up to 30cm for mature plants. Water immediately. Small rosettes can also be planted into a 30cm pot or growing bag filled with peat-free multi-purpose compost.

Maintain steady moisture, especially while plants are young and in containers. Water in dry weather, ideally in the morning so plants grow through the day and the soil surface is less attractive to slugs overnight. Avoid midday watering in heat, when much of it evaporates.

For crops intended to mature, spread a thick layer of garden compost over damp soil. This holds moisture and suppresses weeds. Mulching is rarely practical for short-lived cut-and-come-again rows. Weed regularly so shallow roots do not compete for water, light or nutrients.

In summer, keep soil moist and use light shade. If a flower stem appears, remove and eat it before the buds open, then harvest the rest of the plant promptly. Other plants from the same sowing are likely to follow, so do not wait for full size.

Baby salad leaves may be ready in about 30 days. Snip a few outside leaves from each plant and leave the centre intact for repeated pickings until flowering starts.

Semi-mature and full-sized heads take about 45–75 days. Harvest while rosettes remain compact and firm, cutting through the base with a sharp knife. Light cooking preserves the succulent crunch of the stems and fresh flavour of the foliage.

Harvest normally runs from early summer into autumn. Cloches and an unheated greenhouse can extend late pickings, while repeated small sowings prevent gaps when individual batches bolt or are eaten by pests.

Pak choi's soft juicy growth attracts slugs, snails and brassica-feeding insects. Fine insect-proof mesh protects foliage from flea beetles and caterpillars, while secure wildlife-safe netting prevents pigeon damage. Rotate brassicas and keep beds weed-free.

Common problems