How to Grow Pak Choi: Sowing, Spacing, Bolting & Harvest

Pak choi (also spelled bok choy or pak choy) is one of the fastest, most rewarding vegetables a home gardener can grow. A loose-leaf baby variety can go from seed to plate in about three to four weeks, and a full-size head in six to eight — all from a plant that is happy in a container, a raised bed, or a gap between slower crops. The catch is timing. Pak choi is a cool-season brassica that bolts (runs to flower) the moment it gets hot or stressed, turning sweet, succulent stems bitter overnight. Master the seasonal windows, sow in succession, and keep the plants moving with steady water and you will harvest crisp, mild pak choi from early spring well into autumn. This guide covers varieties, exact timing, spacing, the bolting problem, pests, and how to harvest for repeat cuttings.

Choosing a Variety

Pak choi comes in two broad forms. Full-size types like ‘Joi Choi’ and ‘Black Summer’ form upright heads with thick white or green stalks and dark leaves, ready in roughly 45-60 days. Baby and dwarf types like ‘Toy Choi’, ‘Mei Qing Choi’ (a green-stemmed type), and ‘Shanghai Green’ stay small, mature in 30-45 days, and are ideal for tight spacing, containers, and stir-fries where you cook the whole little head. For warm-weather sowings, look specifically for bolt-resistant or “slow-bolting” varieties — ‘Black Summer’ and many F1 hybrids are bred to hold longer before flowering, buying you a wider planting window.

When to Plant: Timing Is Everything

Pak choi grows best when temperatures sit between about 55°F and 70°F. Above the mid-70s, and especially as days lengthen toward midsummer, the plant senses that conditions are turning unfavorable and switches to making a flower stalk instead of leaves. That means two prime windows in most climates.

Spring: Sow from a few weeks before your last frost through mid-spring, once the soil has warmed to at least 50°F. Sowing into cold, wet soil is a classic mistake — the cold-shock itself can trigger premature bolting later. In spring, lean toward bolt-resistant varieties because lengthening days work against you.

Autumn: This is the easier, more reliable season. Sow from about 6-10 weeks before your first expected fall frost, as summer heat fades. Shortening days and cooling temperatures suit pak choi perfectly, and the crop matures into the gentle conditions it loves — autumn pak choi is usually sweeter and far less likely to bolt. In mild-winter regions you can keep sowing through much of the cool season; understanding the difference between warm-season and cool-season vegetables makes this timing intuitive.

Sowing and Spacing

Pak choi can be direct-sown or started in modules and transplanted, but it has a slight preference for being direct-sown because it dislikes root disturbance — transplant shock is itself a bolting trigger. If you do transplant, do it young (within 2-3 weeks of sowing) and water it in well to minimize stress.

Sow seeds about a quarter to half an inch deep. They germinate fast, often in 4-7 days in warm soil. Thin in stages: for full-size heads, end at 6-10 inches between plants with about 12 inches between rows; for baby pak choi, 2-4 inches apart is fine, and you can even broadcast-sow and harvest as cut leaves. Do not let seedlings crowd — competition stresses them and invites bolting. Eat your thinnings; even tiny pak choi seedlings are good in salads.

Succession Sowing for a Steady Supply

Because pak choi matures so quickly and does not hold long in the ground before bolting, a single large planting gives you a glut followed by nothing. The fix is succession sowing: sow a short row or a small block every 2-3 weeks through your spring and autumn windows. Each sowing matures a couple of weeks after the last, giving you a continuous trickle of tender heads instead of a wall of plants all bolting at once. A few feet of row at a time is plenty for most households. This same approach works for other fast greens, so you can interplant pak choi with crops on different schedules.

Soil, Water, and Feeding

Pak choi wants rich, moisture-retentive soil and steady water. Work in a couple of inches of compost before sowing; as a leafy brassica it appreciates nitrogen and grows best when it never checks (pauses) its growth. The single most important cultural practice is consistent moisture — pak choi has shallow roots and bolts or turns stringy if it dries out, then floods. Aim for evenly damp soil, water deeply at the base, and mulch to buffer moisture and temperature. In hot spells, a little afternoon shade keeps plants cooler and slows bolting.

If your soil is poor, a balanced feed or a nitrogen-leaning organic feed (such as a fish or seaweed solution) every couple of weeks keeps leaves lush and fast. Do not overdo nitrogen, though, as soft floppy growth is more attractive to pests. Good soil is the foundation of every leafy crop; if you are unsure what you are working with, our guide to clay vs sandy soil explains how to improve either for fast greens.

Why Pak Choi Bolts (and How to Prevent It)

Bolting is the number-one frustration with pak choi. When the plant sends up a central flower stalk, the leaves turn bitter and tough and the harvest is essentially over. Three things trigger it: heat (sustained temperatures above the mid-70s), long days (the lengthening daylight of late spring and summer), and stress of any kind — drought, transplant shock, root crowding, or the cold-shock of being sown too early into chilly soil.

You cannot stop pak choi from bolting forever, but you can delay it long past harvest. Sow in the cool windows rather than into summer. Choose bolt-resistant varieties for any spring or marginal sowing. Keep the soil evenly moist so the plant never droughts. Avoid transplant shock by direct-sowing or transplanting very young. And harvest promptly once heads are ready rather than leaving them in the ground hoping they will get bigger — a mature head left standing in warming weather will bolt. If a plant does start to bolt, harvest it immediately and use it before the bitterness sets in.

Pests and Problems

Flea beetles are the classic pak choi pest, peppering the leaves with tiny shot-holes, especially in warm weather and on spring sowings. The most effective defense is to cover the bed with insect-proof mesh or floating row cover from the moment you sow, before the beetles find the seedlings. Slugs and snails shelter in the dense rosettes and shred leaves overnight — patrol after dark, use barriers or traps, and keep the bed tidy. Cabbage white caterpillars and aphids also target brassicas; row cover handles both. Because pak choi is a brassica, rotate it so it does not follow other cabbage-family crops in the same ground, which helps avoid clubroot and soil pests.

Harvesting Pak Choi

You have flexibility. For cut-and-come-again baby leaves, snip the outer leaves with scissors when they are a few inches tall and leave the center to regrow — a single plant can give several pickings. For whole heads, cut the entire plant at the base with a knife once it has formed a firm rosette, usually 45-60 days from sowing. Harvest in the cool of the morning when leaves are crisp and hydrated. Do not wait too long: an over-mature head left in warm weather will bolt and turn bitter, so it is better to cut a head slightly early than to lose it. Pak choi does not store long; use it within a few days, kept cool and slightly damp, or freeze cooked. The crisp white stalks and tender green leaves cook in minutes — stir-fry, steam, or add to soups and noodles.