Why is my plant bolting?

Bolting is triggered by rising temperatures and longer daylight hours.

Can I eat the flowers?

Yes, the yellow flowers are edible and have a mild, peppery flavor.

Plant guide

Pak Choi.

Brassica rapa

Pronounced BRASS-ih-kuh RAH-pah

Also known as Bargeman's Cabbage, Bird's Rape, Birdsrape Mustard, Bok choy, Braze, Colbaga, Field Mustard, Horuhoru

Brassica rapa — Photo by mel letterman (CC BY) via gbif

Pak choi is a fast growing leafy green that loves cool weather. It is a staple in many kitchens because it is so easy to grow and harvest. You will love how quickly it goes from seed to your dinner plate.

At a glance

Care level: Easy
Plant type: Annual vegetable
Light: Full sun to partial shade
Indoor light: Direct sun
Water: Every 2 to 4 days
Mature size: 12 to 18 inches
Growth rate: Fast
Hardiness: USDA 2 to 11
Bloom time: Late spring to early summer

Care

Keep the soil consistently moist to prevent the plant from bolting prematurely. Watch for cabbage worms or aphids on the undersides of leaves. Harvest the outer leaves as you go or cut the whole head once it reaches your preferred size.

Watering: Keep the soil evenly moist but never soggy to encourage steady growth.
Feeding: Use a balanced organic fertilizer to support leafy growth.
Pruning: Remove any yellowing or damaged outer leaves to keep the plant healthy.
Repotting: As an annual vegetable, this plant is typically grown from seed to harvest in one season.
Soil: Rich, well draining, loamy soil
Soil pH: 6.0 to 7.5
Temperature: 5 to 25°C
Humidity: 40 to 70%
Drought tolerance: Low
Lifespan: Annual or biennial, typically 1 season.
Deer and rabbits: Low

Signs it needs repotting

Roots circling the bottom of the container.
Stunted growth despite regular feeding.

Safety

People: The plant is non-toxic and widely consumed as a vegetable.
Children: No specific risks exist for children, though raw plant material should be washed.
Contact allergens: Some individuals may experience mild skin irritation from handling raw leaves due to glucosinolates.
Airborne allergens: Pollen can trigger seasonal allergies in sensitive individuals during the flowering phase.
Edibility: Wash leaves thoroughly to remove soil and potential insect residue before consumption.

How to identify it

Thick, white, crunchy leaf stalks
Dark green, glossy, spoon shaped leaves
Upright, vase shaped growth habit
Soft, tender texture when cooked

Height: 0.3 to 0.6m
Spread: 0.2 to 0.4m
Leaves: green, blue-green, deciduous
Flowers: yellow, 1 to 2cm
Fruit: brown, Summer

Problems to watch for

Flea beetles · Small jumping beetles that chew tiny holes in the foliage.

By symptom

Plant problems by symptom

Check your pak choi from a photo

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Growing it

Propagation: seed
When to plant: early spring, late summer
Overwintering: In mild climates, it can survive the winter outdoors. In colder regions, it is best grown as a seasonal crop.
In containers: It grows well in containers at least 20 cm deep, provided they have good drainage.

Direct Sowing

1. Prepare loose, fertile soil in a sunny spot.
2. Sow seeds 1 cm deep in rows.
3. Keep the soil consistently moist until germination.
4. Thin seedlings to 15 cm apart once they have two sets of true leaves.

Plant in succession every two weeks to ensure a steady harvest throughout the cool season.

Grows well with

Lettuce · They share similar moisture needs and occupy different root depths.
Onion · Onions may help deter certain pests that target brassicas.

Keep away from

Strawberry · Strawberries are known to stunt the growth of many brassica species.

Similar species

Mustard · It is a closely related leafy green with a much spicier flavor profile.

Science

Family: Brassicaceae
Genus: Brassica
Order: Brassicales
Class: Magnoliopsida
Native range: Temperate regions of Eurasia.
Conservation: This species is widely cultivated and not of conservation concern.

It thrives in cool, moist conditions and often colonizes disturbed soil.

Value to wildlife: nectar source
Pollinators: bees, butterflies
Uses: culinary vegetable, cover crop, fodder

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 2/9
Soil reaction: 6/9
Light: 7/9
Temperature: 4/9
Moisture: 6/9
Nutrients: 7/9

Taxonomy resolved against GBIF.

Questions people ask

Why is my plant bolting?: Bolting is triggered by rising temperatures and longer daylight hours.
Can I eat the flowers?: Yes, the yellow flowers are edible and have a mild, peppery flavor.

Where the name comes from

The genus name Brassica is the classical Latin name for cabbage, while rapa refers to the turnip-like root.

Good to know

It is one of the most economically important vegetable species globally.
The plant has been cultivated for thousands of years across Asia and Europe.
It grows very quickly, often ready for harvest in just 4 to 6 weeks.

Keep your pak choi growing

This page is a general guide. Save your plant in Pocket Botanist and you get care reminders timed for this plant, plus a care history that shows what worked.

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This guide was generated with AI on September 26, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.