Choy Sum 'Green Lance' (Green Lance choy sum) care

Light

Most houseplants will scorch where choy sum 'green lance' thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. Full sun, 6+ hours, drives strong stem and bud production; light shade is tolerated and can help in hot weather to slow over-fast flowering. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.

Watering

For choy sum 'green lance' in the ground or in a bed, aim for keep consistently moist; water when the top 2-3 cm is dry, roughly every 2-3 days in warm weather. Soak the root zone rather than misting the foliage; deep, less-frequent watering trains roots downward and produces a more drought-resilient plant by mid-season. Even moisture keeps stems thick, sweet, and crisp. Drought stress makes stems stringy and bitter and hastens flowering. Avoid waterlogging.

Soil and pot

Choy Sum 'Green Lance' grows best in rich, free-draining loam. Fertile, organic-rich, well-drained soil, pH 6.0-7.5. Lime acidic soils toward neutral to deter clubroot. Suits deep containers with nutrient-rich potting mix. 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

Choy Sum 'Green Lance' sits happiest at around 40-70% humidity and 15-25°C (59-77°F). Field crop indifferent to ambient humidity; steady soil moisture is the priority. Adequate spacing limits fungal disease in muggy spells. 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 choy sum 'green lance' sparingly. Fast, hungry crop: prepare beds with compost or balanced fertiliser, then feed with a nitrogen-rich liquid feed every 2 weeks for lush stems, easing off slightly as flower 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 choy sum 'green lance' in the Growli community. Each is annotated with the most common cause so you know where to start.

• Premature bolting — Heat, transplant shock, or stress makes plants flower and run to seed too fast. Sow at the right season, keep moist, and harvest stems promptly.
• Flea beetles — Shot-hole damage on seedling leaves slows establishment. Protect with fine mesh and grow young plants on quickly.
• Aphids — Cluster on tender stem tips and buds, fouling them. Blast off with water, encourage ladybirds, or use insecticidal soap.
• Clubroot — Distorted, swollen roots and wilting in infected brassica soils. Rotate crops, lime to near-neutral pH, and improve drainage.

Propagation

From seed. Direct-sow 1 cm deep and thin to 15-20 cm, or start in modules and transplant young. Successional sowings every 2-3 weeks keep stems coming. 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

Choy Sum 'Green Lance' is mildly toxic to pets. ASPCA lists cultivated Brassica/Indian Mustard species as toxic to horses (toxic principle: isothiocyanates; signs include GI irritation and colic). Cats and dogs are not flagged as toxic on that entry and tolerate small cooked amounts, but isothiocyanates and oxalates can cause stomach upset, and large repeated quantities carry thiocyanate risk, particularly in cats. Keep away from horses; verify with a vet if a pet seems unwell. 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.

Choy Sum 'Green Lance' deep-dive guides

Every aspect of choy sum 'green lance' care, each with its own calibrated guide:

• Choy Sum 'Green Lance' watering schedule
• Choy Sum 'Green Lance' light requirements
• Best soil mix for choy sum 'green lance'
• Choy Sum 'Green Lance' fertilizing guide
• When to repot choy sum 'green lance'
• How to propagate choy sum 'green lance'
• Choy Sum 'Green Lance' growth rate & size
• Choy Sum 'Green Lance' cold hardiness
• Choy Sum 'Green Lance' temperature & humidity
• Is choy sum 'green lance' toxic to cats & dogs?
• Is choy sum 'green lance' toxic to cats?
• Is choy sum 'green lance' toxic to dogs?

Related guides

Choy Sum 'Green Lance' is also commonly called Green Lance choy sum or Chinese flowering cabbage.

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