Asian Greens / Mustards · Cool-season annual (biennial) leafy vegetable; open-pollinated

Pac Choi 'Prize Choy' New · Sep 2026

Brassica rapa var. chinensis 'Prize Choy'· Pac choi, Pak choi, Bok choy

FallSpring

Pac Choi 'Prize Choy' — Young — Seedling / just planted
Young pac choi transplants at the 4-6 true-leaf stage, a week or two after setting out in a garden bed, still small with pale stems just forming.

Species-level photo (not this exact cultivar).

Photo: Forest and Kim Starr· CC BY 3.0 us

Pac Choi 'Prize Choy' — Growing — Established, filling in
Half-grown pac choi in field rows on drip irrigation, plants about 6-8 in tall with stems thickening, roughly 3 weeks from harvest.

Species-level photo (not this exact cultivar).

Photo: Forest and Kim Starr· CC BY 3.0 us

Pac Choi 'Prize Choy' — Full grown — What you’re aiming for
Full-size white-stem pac choi in the garden with thick celery-like white stalks and big dark-green leaves, the vase-shaped head Prize Choy is grown for.

Species-level photo (not this exact cultivar).

Photo: Webvet~enwiki at English Wikipedia· Public domain

Planting window · Zone 8a, Decatur

Decatur (Zone 8a): sow in cell trays in mid-August to early September and transplant in September to early October, or direct sow from late August to late September, for heads from mid-October through December;

Growing stages

What to look for, and what to do, at each point in its life

This group (mizuna, pac choi varieties Rosie F1, Baby Choi, and Prize Choy, and mustards Ruby Streaks, Red Giant, and Southern Giant) follows the same fall-through-spring rhythm as the other greens in Decatur, sown in September for a winter harvest and again in February-March before spring heat pushes them to bolt, but several of these mustards will happily reseed themselves if you let a plant flower.

1
Sowing
Early-mid September (fall crop) or mid-February to early March (spring crop)

You'll see Seeds are small and round, reddish-brown for mustards and pac choi, and show nothing above ground for several days after sowing.

Do Direct sow 1/4 inch deep, or start pac choi varieties in cell trays for a head start, and keep the surface consistently moist.
2
Seedling
Days 4-18 after sowing

You'll see Round seed leaves appear first, then true leaves show each variety's character: mizuna's deeply feathered leaf, pac choi's smooth spoon shape, and the mustards' ruffled, sometimes reddish-purple edges (Ruby Streaks and Red Giant color up early, even as seedlings).

Do Thin to 4-6 inches apart for mizuna and mustards, 6-8 inches for pac choi, and watch for flea beetle shot-holes.
3
Transplant
3-4 weeks after starting indoors, when seedlings have 2-3 true leaves

You'll see Transplant-ready pac choi seedlings are compact, 2-3 inches tall, with a small but well-formed rosette and a root ball that holds together.

Do Harden off over 5-7 days, then set plants at the same depth they grew, spaced 8-10 inches apart for pac choi in beds or grow bags.
4
Cut-and-come-again harvest
Starting 25-40 days after sowing, continuing 4-8 weeks

You'll see Leaves reach 4-8 inches, with pac choi forming a loose vase-shaped rosette and mustards and mizuna forming a spreading clump of individual leaves.

Do Harvest outer leaves first, or shear the whole plant an inch above the crown for a quick regrow.
5
Bolting
Late spring, typically May, once daylength lengthens and temperatures push past 75-80°F

You'll see A central stalk shoots up, leaves become sparse and pointed, and small yellow four-petaled flowers cluster at the top, a classic mustard-family (Brassica) bloom.

Do Harvest what you can before leaves turn bitter, then either pull the plant or leave a few to flower for pollinators and seed.
6
Seed saving
4-8 weeks after bolting, once seed pods dry from green to brown

You'll see Flower stalks turn from bright yellow blooms to slim, brown, brittle pods that rattle with seed when dry.

Do Cut dry seed stalks into a paper bag, finish drying, then crush and winnow to collect seed; note which varieties are worth saving.

Techniques — transplant, prune, propagate, divide, seed

At a glance

Botanical name: Brassica rapa var. chinensis 'Prize Choy'
Family: Brassicaceae (mustard family)
Type: Cool-season annual (biennial) leafy vegetable; open-pollinated
Native range: Pac choi was domesticated in China and grown there for over 1,500 years.
Hardiness: Zones Grown as an annual in all zones; in Zone 8a a fall, winter (with cover) and early-spring crop
Height: 15-18 in tall heads at full size; 3 in for baby-leaf cutting

Sun

Full sun to part shade; 6 hours is ideal, 4 is workable, and it will limp along with 2…

Water

Even moisture, 1 to 1.5 in per week for these big heads; drought or irregular watering…

Spacing

Full-size heads: thin or transplant to 8-12 in apart in rows 12-18 in apart.

Soil

Rich, moist, well-drained soil high in organic matter, pH 6.0-7.5.

Care

Start in 72-cell trays 3-4 weeks before planting and set out young, or direct sow 1/4 in deep and thin to 8-12 in at the 3-leaf stage.
Work 2 in of compost into the bed plus a balanced organic fertilizer; side-dress with fish emulsion or blood meal at 3 weeks because big heads need steady nitrogen.
Mulch with straw or shredded leaves after thinning to hold moisture and keep soil off the white stems.

Good to know

Luke's tag says Prize Choi; the seed trade spells it Prize Choy. As of September 2026 Johnny's Selected Seeds does not list this variety (a site search returns no product), so it could not be verified there;

Where it fits

Give it the front or middle of the brassica bed with 8-12 in of elbow room; interplant quick mizuna, radishes or baby lettuce between heads and harvest them before the pac choi fills in.

Harvest

Cut whole heads at the soil line when 12-18 in tall and firm (about 50 days); in fall this is usually late October to December.

In the kitchen

Mild, sweet and juicy; the celery-like white stems stay crisp when cooked and the leaves wilt tender.

Watch for

Flea beetles, cabbage worms, diamondback moth, harlequin bugs, yellow-margined leaf beetles, aphids, cabbage root maggot, slugs and snails.

Wildlife & pollinators

Host plant for cabbage white and cabbage looper caterpillars; flowers attract bees and hoverflies if it bolts.

Toxicity

None known; safe for people and pets in normal food amounts. Contains goitrogens like all brassicas.

Propagation

Seed; open-pollinated, so seed can be saved if a few plants are allowed to overwinter and flower in spring and are isolated from other flowering…

General Asian Greens / Mustards guide

Transplant in the evening; shade cloth the first 3–5 days if highs are above 85°F.
Row cover (AG-19) from day one keeps cabbage worms, flea beetles and harlequin bugs off — the #1 fall greens fix.
Sow a new short row every 2–3 weeks through October for a continuous harvest.
Harvest outer leaves and let the center keep producing (cut-and-come-again); or cut whole plants 1" above the crown and they'll regrow once.
Mustards and mizuna shrug off frost and freezes into the low 20s; pac choi needs row cover below ~28°F.
Let one plant bolt in spring — the yellow flowers feed bees and the seed comes true for open-pollinated types.

Sources (7)