Vegetable
Bok choy (pak choi)
Brassica rapa subsp. chinensis · Brassicaceae
Also called: Pak choi, Chinese white cabbage, Bok choi
Bok choy (pak choi) (Brassica rapa subsp. chinensis) is a moderate-water vegetable well suited to Tucson and the low desert. It thrives in full sun in cool months.
Bok choy (pak choi) at a glance
- Water use
- Moderate (established)
- Sun
- Full sun in cool months; provide light afternoon shade for late plantings to slow bolting in warming weather.
- Mature size
- 6-12 in tall and wide (baby types smaller, 4-6 in).
- Growth rate
- Fast (about 30-50 days from seed; baby bok choy in 30 days).
- Bloom
- Yellow (bolting; signals end of harvest), Harvest fall through spring in Tucson; bolts (flowers) with heat and long days.
- Cold hardiness
- Cool-season crop, frost-hardy to about 25-28 F; grown through Tucson winters. USDA 9a-9b.
- Soil
- Rich, moisture-retentive, well-drained loam amended with compost; pH 6.0-7.5, tolerates alkaline desert soil.
- Native range
- China / East Asia (long cultivated)
- Best used as
- Edible leafy vegetable (stir-fry, soups, salads), Fast cool-season raised-bed crop, Succession and intercropping
- Wildlife
- Flowers attract bees if bolted; foliage prone to aphids, flea beetles, and cabbage loopers, use row cover.
- Toxicity
- Non-toxic and edible for humans and pets.
How to grow Bok choy (pak choi) in Tucson & the low desert
Watering
Cool-season planting: per the Pima County guide, sow/transplant Sep-Dec (fall) and Jan-Feb (late winter). Keep soil consistently moist; water deeply 2x/week. Moisture stress and heat trigger bolting, so plant well within the cool window.
Fertilizer & nutrients
Moderate feeder. Mix compost and a balanced or nitrogen-leaning fertilizer into the bed at planting; a light nitrogen side-dress midway keeps leaves lush and fast.
Pruning & care
No pruning. Harvest whole heads, or pick outer leaves for cut-and-come-again. Harvest before the plant bolts as days lengthen and warm.
Notes
Among the quickest and easiest cool-season greens for Tucson; succession-sow every 2-3 weeks through fall and winter. Heat-sensitive, so finish harvest before spring temperatures climb. Not native.
Sources: University of Arizona Cooperative Extension - Pima County Vegetable Planting and Harvesting Guide, shows Bok Choy S/T Jan-Feb and S Sep-Dec (extension.arizona.edu); University of Arizona Cooperative Extension - October Monthly Gardening Guide for Pima County (extension.arizona.edu)