Plant family

Bok choy belongs to the brassica family (Brassicaceae, the cabbage or mustard family), along with close relatives such as cabbage, broccoli, cauliflower, kale, Brussels sprouts, collards, turnips, radishes, mustard greens, and arugula. All of these share many of the same pests and diseases, so gardeners should treat them as one group when planning rotations.

Why rotate bok choy

When bok choy or its brassica relatives grow in the same spot year after year, soilborne problems like clubroot, black rot, and fusarium yellows can build up and persist in the soil for years. Pests that favor this family, including cabbage root maggot, flea beetles, cabbage aphids, and cabbage loopers, also accumulate when a host crop is always available. On top of that, bok choy is a heavy nitrogen feeder, so repeated plantings can leave the bed depleted.

What to plant after

Bok choy does well following legumes such as bush beans, peas, or a clover cover crop, because legumes fix nitrogen in the soil and leave it richer for a hungry leafy crop. It can also follow fruiting crops like tomatoes or squash, or alliums like onions and garlic, since none of these share brassica diseases. Any predecessor that adds fertility or breaks the pest cycle sets bok choy up for tender, fast growth.

What to avoid

Avoid planting bok choy right before or after other members of the brassica family, including cabbage, broccoli, cauliflower, kale, radishes, turnips, and mustard greens. Growing these back to back keeps clubroot spores and cabbage-family pests fed and active in the same soil. Give a bed a break from all brassicas for several years rather than swapping one for another.

Example rotation

A simple four-year, four-bed rotation works well: Year 1 grow legumes (peas or bush beans) to build nitrogen, Year 2 plant bok choy and other brassicas in that enriched bed, Year 3 follow with fruiting crops like tomatoes or squash, and Year 4 grow alliums or root crops such as onions, carrots, or beets. Each family then moves one bed forward the next season, so bok choy only returns to a given bed once every four years.

Tips

Keep a simple garden map or notebook each season so you always know where the brassicas grew and can wait at least three to four years before returning them to the same bed. Sowing a legume or grass cover crop in the off-season helps rebuild fertility and soil structure before bok choy comes back around.

General guidance for US home gardens. Adapt to your own crops, soil, and space; your Cooperative Extension office can help with a plan for your area. Page updated Aug 4, 2026.