Bok Choy
Brassica rapa subsp. chinensis
Six weeks from sowing to harvest, and it bolts the moment days get long and warm.

Autumn is the reliable season
Bok choy is Brassica rapa, and long warm days send it straight to flower. Spring sowings frequently bolt before they head. Sow from late summer into early autumn, when days are shortening and temperatures falling, and it behaves completely differently.
Baby or full size
Sow at six inches and harvest whole as baby bok choy at four to six weeks, or thin to ten inches for full-size heads. Baby is more tender and quicker; full size gives more per square foot.
Keep it growing fast
Quality depends on uninterrupted growth. Rich soil, steady water and a nitrogen side-dress keep the ribs thick and juicy. Slow-grown plants are stringy and bolt sooner.
Flea beetles
They shred young brassica leaves in spring and late summer and can wipe out a seedling stand. Floating row cover from sowing is the simplest and most effective answer, and no pollination is needed.
Slugs
The dense low rosette and thick white ribs are ideal slug habitat, especially in a wet autumn. Check under outer leaves; iron phosphate bait or evening hand-picking both work.
Harvest
Cut the whole plant at soil level. Cutting an inch above the crown often produces a smaller second flush. Harvest before any sign of a flower stalk - once it bolts the ribs turn bitter and fibrous.
Overwintering
Under a low tunnel it holds through much of a zone 6b/7 winter, growing slowly and staying in good condition. One of the best cold-frame crops available.
Kitchen and storage
Keeps about a week in the fridge in a bag. The white ribs and green leaves cook at different rates - separate them and start the ribs first. Excellent in stir fries, braises and soups.
- Days to harvest
- 40-55
- Spacing
- 6-10 in
- Row spacing
- 12-18 in
- Sun
- Full to part
- pH
- 6.0-7.5
- Bolts above
- ~75F
- Best season
- Fall
- Water
- Steady, never dry