Growing Choy Sum in Australia: The Complete Guide

Choy Sum is an easy brassica to grow, needing full–part sun with consistent watering.

We get asked about choy sum often enough that it's worth setting out the full picture here, beyond what fits on our printable card.

Every crop earns its place in a garden differently, and choy sum is no exception. At a glance, it's rated easy, with a sun of full–part sun; water of consistent; soil ph of 6.0–7.0 — details that matter more once you're actually planning around them than they do on a first read. The rest of this article works through exactly what each of those means day to day, in more depth than a single printable card has room for, and with the reasoning behind each recommendation rather than just the recommendation itself.

Climate and Timing Considerations

Australia's climate zones change growing timing more than most general advice accounts for. Cool temperate zones (Tasmania, the Victorian highlands, southern NSW) have recurring frost risk well into what other zones call spring, which compresses the safe planting window for frost-tender plantings. Warm temperate zones (Sydney, Adelaide, Melbourne, Perth) sit closest to what general advice assumes by default. Subtropical zones (Brisbane, northern NSW) rarely see frost at all, and the growing calendar shifts earlier and later as a result. Our site-wide zone setting adjusts the advisory note shown on the Planting Calendar for exactly this reason — worth setting once if you haven't already. The same zone setting also feeds the Harvest Calendar, so both ends of the growing cycle reflect wherever you actually garden, rather than a generic Australia-wide average.

• Cool Temperate (TAS, VIC highlands, southern NSW, ACT): shorter frost-free window — lean toward the later end of any spring planting window shown on the guide above.
• Warm Temperate (Sydney, Adelaide, Melbourne, Perth, coastal NSW/WA): closest match to the general timing shown above; frost is occasional but rarely severe.
• Subtropical (Brisbane, northern NSW, coastal QLD): minimal frost risk — often plantable a few weeks earlier and later than the general window shown above.

Grown for the flowering stem

Unlike its leafy relatives, choy sum is picked for its tender stems and edible yellow flowers, harvested while still young before the stems toughen.

Getting Choy Sum Into the Ground

Method. Direct sow or transplant seedlings.

Soil. Rich, moisture-retentive.

Timing. Sow year-round in mild zones; avoid the height of summer heat.

It's worth reading these as a set rather than in isolation; they reinforce each other.

Ongoing Care

Keep these points in mind:

• Keep soil consistently moist for tender, non-bitter stems.
• Succession sow every 2–3 weeks for a continual harvest.
• Net against cabbage moth if pressure is high.
• Harvest promptly once flower buds appear — stems toughen quickly after.

Each of these compounds over a season — small misses early tend to show up later — keep soil consistently moist for tender, non-bitter stems. Harvest promptly once flower buds appear, since stems toughen quickly after. Treat this list as a routine to build rather than a one-off checklist, and it becomes second nature within a season or two.

Common Problems

Worth paying attention to:

• Bolting — heat stress; grow in cooler months.
• Cabbage moth — net or hand-pick.
• Slugs and snails — target young leaves; use barriers.
• Tip burn — irregular watering; keep moisture even.

Getting these details right matters more than it might seem — bolting — heat stress; grow in cooler months. Tip burn — irregular watering; keep moisture even. Treat this list as a routine to build rather than a one-off checklist, and it becomes second nature within a season or two.

Harvest and Storage

Signs. Stems firm and upright, flower buds just forming or starting to open.

Method. Cut stems 5–10cm above the base; the plant regrows for a second harvest.

Curing. None needed.

Storage. Fridge crisper, a few days — best used fresh.

Taken together, these are the details that separate a smooth result from a frustrating one.

Preserving. See Fermenting for sauerkraut and fermented brassicas, or Freezing Produce for blanching and freezing a glut.

Companions & rotation

Our printable card above lists specific plants that pair well nearby and others best avoided, along with a rotation note: Onion, Herbs, Strawberry, Tomato. Getting this right matters more over multiple seasons than it does in any single one — the benefits and the risks of poor rotation both compound over time rather than showing up immediately.

Related Guides

If choy sum suits your garden, these related guides in the same category are worth a look too:

• Bok Choy
• Broccoli
• Brussels Sprouts
• Cabbage
• Cauliflower

For the condensed, printable version of everything above, head to the main choy sum guide page. Companion planting and bed rotation both make a measurable difference over a season, and our Companion Planting Checker takes the guesswork out of both. As with every guide on this site, this is general information based on our own research and experience, not professional advice — your specific soil, climate, and circumstances will always vary from ours to some degree.

Beyond the printable card, our Planting Calendar and Harvest Calendar tools will show a zone-adjusted note for choy sum specifically, and the Companion Planting Checker covers the specific pairings mentioned above in more detail.

Frequently Asked Questions

→ View the printable A4 guide for choy sum