When to Plant Choy Sum in Cairns, Tropical Guide
Soil temperature is modelled from Open-Meteo forecast (Cairns), not a live sensor.
What this month normally looks like in Tropical
In October the Tropical zone normally runs 34°C by day and 23°C overnight, with about 53 mm of rain over 5 or 6 wet days. Averages 1991 to 2026, 37 postcodes, SILO.
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This Choy Sum guide is written for the Tropical zone, which takes in Cairns, Townsville and Darwin. Somewhere else? Your postcode picks the right one.
Not your zone? Brisbane Sydney Melbourne Canberra Alice Springs Perth
Also handy: will it frost this week? and what grows in shade.
- Planting window
- Apr to Aug
- Days to harvest
- 49 days
- Sun
- Full sun to part shade
- Soil pH
- 6.0–7.5
Choy sum is a fast-growing Asian leafy green with tender green leaves, pale stems and small yellow flowers that are eaten. It is grown as a cool-season annual and picked young.
Published · By GardenBuddy.au
Planting dates, current conditions and prices on this page update daily.
Planting Calendar for Tropical
- Jan -
- Feb -
- Mar -
- Apr D
- May D
- Jun D
- Jul D
- Aug D
- Sep -
- Oct -
- Nov -
- Dec -
S = Seed Tray T = Transplant D = Direct Sow
Want a nudge when it is sowing time?
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How to Grow Choy Sum in Tropical Australia
- Soil
- Rich, fertile, moist, organic-rich well-drained loam
- Salt
- Moderately sensitive. Copes with a little salt, but the harvest drops on salty bore water.
- pH Range
- 6.0-7.5
- Sunlight
- Full sun to partial shade, at least 4 to 6 hours of direct sun a day
- Spacing
- 25-30cm apart, 25cm between rows
- Watering
- Irrigate once or twice a week; use raised beds where waterlogging is a problem
- Good companions
- Nasturtium, Lettuce, Onion, Dill, Beetroot
Tropical Growing Tips for Choy Sum
Recommended Varieties
- Karate F1 (F1 hybrid)
- Taboo F1 (F1 hybrid)
- Choi San (Open pollinated)
Key Challenges
- Diamondback Moth: Caterpillars chew irregular holes, often creating 'windowpane' damage (eating one side of leaf leaving transparent membrane)
- Cabbage White Butterfly: Caterpillars eat large ragged holes in leaves
- Aphids: Sap-sucking, virus transmission
- White Blister: Spoils leaves and can distort young growth
Pro Tips
- Work rich compost or organic fertiliser into soil prior to sowing; apply a nitrogen-rich liquid fertiliser weekly to promote fast stem development
- Apply a light organic straw mulch around plants to retain soil moisture and reduce weeds
Pests and problems for Choy Sum in Tropical
- White Blister Rotate brassicas and avoid overhead watering in humid weather. Watch
- Clubroot Rotate brassicas, keep soil near neutral and do not move infected soil. Watch
- Diamondback Moth Diamondback Moth: Caterpillars chew irregular holes, often creating 'windowpane' damage (eating one side of leaf leaving transparent... Watch
- Cabbage White Butterfly Cabbage White Butterfly: Caterpillars eat large ragged holes in leaves Watch
- Aphids Aphids: Sap-sucking, virus transmission Watch
Harvesting Choy Sum
When ready: Central flower stem forms yellow flower buds just before or right as the first 1 to 2 yellow blossoms open
How to harvest: Cut central flowering stem 5 to 10 cm above ground level with a sharp knife to encourage lateral side shoots
What choy sum costs in the shops right now, retailer by retailer, updated daily.
What members get
- Soil and weather from your nearest station
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- Price history and price alerts
- Pest risk alerts for your area
- Full salt and canning detail
Common Questions About Choy Sum
When do you plant choy sum in Australia?
It depends on your climate zone, not the calendar month alone. Planting months by zone:
- Tropical (Cairns): Apr to Aug
- Subtropical (Brisbane): Mar to Sep
- Warm Temperate (Sydney): Mar to Jun, Aug to Oct
- Cool Temperate (Melbourne): Jan to Mar, Sep to Dec
- Cold / Highland (Canberra): Sep to Dec
- Arid / Semi-Arid (Alice Springs): Mar to Aug
- Mediterranean (Perth): Mar to Jun, Aug to Oct
Can you grow choy sum all year round in Cairns?
No. In the Tropical zone the planting months are Apr to Aug. Outside that window it either bolts, sulks or gets cut down by the weather.
When should I plant Choy Sum in Cairns?
Sow during the cooler dry season months from April to August in rich soil with light partial shade.
What soil temperature do Choy Sum need?
Choy Sum germinate best when soil temperature is between 15°C and 25°C.
How do I know when Choy Sum are ready to harvest?
Central flower stem forms yellow flower buds just before or right as the first 1 to 2 yellow blossoms open
What are the best Choy Sum varieties for Cairns?
Recommended varieties for the Tropical zone include: Karate F1 (F1 hybrid), Taboo F1 (F1 hybrid), Choi San (Open pollinated).
What grows well with Choy Sum?
Good companion plants for Choy Sum include: Nasturtium, Lettuce, Onion, Dill, Beetroot.
Are choy sum salt tolerant?
Only a little. Choy sum are moderately sensitive to salt, so the harvest drops on salty bore water. Mix salty water with rainwater, and mulch the bed.
Which zone am I in?
Type your postcode into the box near the top of the page and it tells you, and links this crop in your own zone if it differs. Or look it up on the grow zone map. This page is the Tropical zone, Cairns is its reference city.