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Plant care

Kai-lan (Gai Lan) (kai-lan) care

Brassica oleracea var. alboglabra

Also called kai-lan, gai lan, Chinese broccoli, Chinese kale.

RHS H3 (tolerates light frost; not reliably hardy through hard freezes)USDA Grown as an annual in zones 2-11Mildly toxic to petsIndoor 30-50 cm tall and 25-40 cm wide.

Watering rhythm

2-4days

Keep evenly moist; water when the top 2-3 cm is dry, about every 2-4 days depending on heat

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Light

Direct sun (at least 4-6 hours)

Soil

Rich, firm, well-drained loam

Humidity

40-70%

Temp

15-28°C

Pet safety

Mildly toxic to pets

Mature size

30-50 cm tall and 25-40 cm wide.

Care at a glance

Light

Aim for at least 4-6 hours of direct sun on the leaves. Full sun, 6+ hours, for sturdy stems and good yields; tolerates light shade, which can help in hot climates to keep growth steady. If your only bright window faces south, that's perfect for kai-lan (gai lan) — same window any aroid would fry on.

Watering

Crops like kai-lan (gai lan) reward consistent watering — keep evenly moist; water when the top 2-3 cm is dry, about every 2-4 days depending on heat. The mistake is the daily light sprinkle: it never reaches the deeper roots. A long soak twice a week beats a five-minute splash every day. Consistent moisture builds thick, tender stems and reduces bitterness. Mulch to conserve moisture; avoid waterlogging that encourages root disease.

Soil and pot

Kai-lan (Gai Lan) grows best in rich, firm, well-drained loam. Fertile, organic-rich soil, pH 6.0-7.5, ideally firmed for steady brassica growth. Lime acidic soils toward neutral to suppress clubroot. Grows in large, deep containers. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Kai-lan (Gai Lan) sits happiest at around 40-70% humidity and 15-28°C (59-82°F). Outdoor crop indifferent to air humidity; soil moisture governs stem quality. Space well for airflow to limit downy mildew and leaf spot. If you keep the room above 15 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed kai-lan (gai lan) sparingly. A hungry brassica: enrich soil with compost or balanced fertiliser before planting, then side-dress with nitrogen-rich feed every 2-3 weeks for vigorous leaves and thick stems; ease off as buds form. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on kai-lan (gai lan) in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Bolting and yellowing buds — Heat or delayed harvest opens the buds and loses sweetness. Cut stems while buds are tight and grow in suitable seasons.
  • Cabbage caterpillars — Cabbage white and looper larvae chew leaves and stems. Net with insect mesh and remove eggs and caterpillars by hand.
  • Clubroot — Swollen, distorted roots and stunting in infected brassica soils. Rotate crops, lime to near-neutral pH, and improve drainage.
  • Cabbage root fly — Larvae attack roots, causing wilting and collapse of young plants. Use collars at the stem base or fleece transplants.

Propagation

From seed. Direct-sow 1 cm deep and thin, or raise in modules and transplant; space 20-30 cm apart. Sow successionally for staggered harvests of stems and shoots. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Kai-lan (Gai Lan) is mildly toxic to pets. Brassica oleracea cultivars are widely treated as safe in moderation for cats and dogs, but the ASPCA's Brassica/Indian Mustard listing is toxic to horses (isothiocyanates; gastrointestinal irritation and colic), and isothiocyanates and oxalates in the genus can cause GI upset, gas, and—rarely, with large repeated amounts—thiocyanate effects in pets. Keep away from horses and consult a vet for any unwell animal. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Kai-lan (Gai Lan) care — frequently asked questions

What is the common name for Brassica oleracea var. alboglabra?

Brassica oleracea var. alboglabra is most commonly called Kai-lan (Gai Lan), but it is also known as kai-lan, gai lan, Chinese broccoli, Chinese kale. The names refer to the same species, so care instructions for Kai-lan (Gai Lan) apply identically to anything sold as kai-lan.

How much light does kai-lan (gai lan) need?

Kai-lan (Gai Lan) grows best in direct sun (at least 4-6 hours). Full sun, 6+ hours, for sturdy stems and good yields; tolerates light shade, which can help in hot climates to keep growth steady.

How often should I water kai-lan (gai lan)?

Water kai-lan (gai lan) keep evenly moist; water when the top 2-3 cm is dry, about every 2-4 days depending on heat. Consistent moisture builds thick, tender stems and reduces bitterness. Mulch to conserve moisture; avoid waterlogging that encourages root disease. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is kai-lan (gai lan) toxic to cats and dogs?

Kai-lan (Gai Lan) is mildly toxic to pets. Brassica oleracea cultivars are widely treated as safe in moderation for cats and dogs, but the ASPCA's Brassica/Indian Mustard listing is toxic to horses (isothiocyanates; gastrointestinal irritation and colic), and isothiocyanates and oxalates in the genus can cause GI upset, gas, and—rarely, with large repeated amounts—thiocyanate effects in pets. Keep away from horses and consult a vet for any unwell animal.

What USDA hardiness zone does kai-lan (gai lan) grow in?

Kai-lan (Gai Lan) is rated for USDA zone Grown as an annual in zones 2-11; more heat-tolerant than heading broccoli, frost-tender in flower and RHS hardiness H3 (tolerates light frost; not reliably hardy through hard freezes). Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Kai-lan (Gai Lan) deep-dive guides

Every aspect of kai-lan (gai lan) care, each with its own calibrated guide:

Related guides

Kai-lan (Gai Lan) is also known as kai-lan, gai lan, Chinese broccoli, and Chinese kale.