When to Plant Radish 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 Radish 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 Jul
- Days to harvest
- 25 days
- Sun
- Full sun to part shade
- Water
- Regular
- Spacing
- 5 cm apart
- Soil pH
- 6.0–7.0
- Shop price
- $14.95/kg at one shop
Radishes are the fastest-growing root vegetable, with some varieties ready in as little as 4 weeks. They are ideal for beginners, succession planting, and filling gaps between slower crops.
Published · By GardenBuddy.au
Planting dates, current conditions and prices on this page update daily.
Photo: Wikimedia Commons
Planting Calendar for Tropical
- Jan -
- Feb -
- Mar -
- Apr D
- May D
- Jun D
- Jul D (likely to bolt)
- Aug -
- Sep -
- Oct -
- Nov -
- Dec -
S = Seed Tray T = Transplant D = Direct Sow
Amber = likely to bolt if sown this month, it matures into heat or long days.
Want a nudge when it is sowing time?
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How to Grow Radish in Tropical Australia
- Soil
- Friable, well-drained soil with good moisture retention. Avoid heavy clay. Compost or aged manure improves results but do not use fresh manure which causes forking.
- Salt
- Moderately sensitive. Copes with a little salt, but the harvest drops on salty bore water.
- pH Range
- 6.0-7.0
- Sunlight
- Full sun in cool months; light afternoon shade in summer to prevent bolting
- Spacing
- 5cm apart, 25cm between rows
- Watering
- Consistent moisture is critical. Radishes grown with irregular water become woody, pithy, and hot. Water lightly every 1-2 days in dry weather. Mulch to retain soil moisture.
- Good companions
- Carrot (as trap crop for flea beetle), Parsnip (as row markers), Watermelon (trap crop for flea beetles), Nasturtium, Dwarf Beans
- Keep away from
- Grape, Hyssop
- Grow before it
- Legumes (Beans - Dwarf, Peas, Broad Beans)
- Grow after it
- Fruiting crops (Tomato, Capsicum, Zucchini)
Give the bed 3 turns before brassicas go back in. The cabbage family is hungry for nitrogen and shares club root and other soil diseases.
Tropical Growing Tips for Radish
Recommended Varieties
- White Icicle
- Cherry Belle
- French Breakfast
- Daikon (Oriental winter radish)
Key Challenges
- Rapid bolting in summer heat
- Flea beetle and caterpillar pressure year-round
- Pithy roots in hot weather
Pro Tips
- Focus on the dry season for best quality roots
- Harvest early (3-4 weeks) before roots become pithy
- Use shade cloth (30-50%) for summer sowings
Pests and problems for Radish in Tropical
- Diamondback Moth Watch
- Cabbage White Butterfly Watch
- Damping Off Sow into warm, well-drained soil. Avoid overcrowding. Do not overwater seedlings. Use clean, fresh compost. Watch
- Common Garden Snail Watch
- Slugs Watch
- Clubroot Maintain soil pH above 6.5 (lime if acidic). Improve drainage. Buy disease-free seedlings. 7+ year rotation for brassicas in infected... Watch
- Flea beetle Flea beetle and caterpillar pressure year-round Watch
Harvesting Radish
When ready: Round varieties: shoulder visible at soil level, 2-3cm diameter. Pull one to check. Summer types: harvest at 4-6 weeks before they become pithy. Winter/daikon types: harvest at 8-10 weeks when 15-25cm long.
How to harvest: Grasp foliage near the crown and pull gently. Water the bed beforehand if soil is dry. For daikon/winter types, loosen soil alongside the root with a fork first.
Storing and preserving radish
How to keep it
- Refrigerator Storage. Remove tops (they draw moisture from the root). Store unwashed roots in a plastic bag with a damp paper towel in the crisper drawer. Keeps: 2-4 weeks (summer types); 2-3 months (winter/daikon types).
- Fermenting (Lacto-fermented). Slice radishes and pack into a jar with 2% salt brine (20g salt per litre water). Submerge under brine with a weight. Ferment at room temperature for 3-7 days, tasting daily. Refrigerate when tangy to your liking. Keeps: 3-6 months refrigerated.
- Dehydrating. Slice thinly (2-3mm). Dehydrate at 55C for 6-8 hours until crisp. Store in airtight containers. Use as crunchy snacks or rehydrate in soups. Keeps: 12 months.
- Pickling. Slice or halve radishes. Pack into sterilised jars. Cover with hot brine (1 cup vinegar, 1 cup water, 2 tbsp sugar, 1 tbsp salt). Add spices (chilli, garlic, dill). Seal and refrigerate. Ready in 24 hours. Keeps: 4-6 weeks refrigerated.
- Daikon: Traditional Asian Preservation (Takuan). Sun-dry whole daikon for 1-2 weeks until flexible. Pack with rice bran, salt, and sugar in a crock. Weight down. Ferment for 1-3 months. The result is yellow, crunchy, pungent pickled radish. Keeps: 6-12 months.
What radish costs in the shops right now, retailer by retailer, updated daily.
What members get
- Soil and weather from your nearest station
- An email when it's time to sow
- Your own garden plan, including planning from a photo
- Price history and price alerts
- Pest risk alerts for your area
- Full salt and canning detail
Common Questions About Radish
When do you plant radish in Australia?
It depends on your climate zone, not the calendar month alone. Planting months by zone:
- Tropical (Cairns): Apr to Jul Likely to bolt if sown in July.
- Subtropical (Brisbane): all year Likely to bolt if sown in August, September, October and November.
- Warm Temperate (Sydney): all year Likely to bolt if sown in October, November and December.
- Cool Temperate (Melbourne): all year Likely to bolt if sown in October, November and December.
- Cold / Highland (Canberra): Jan to Apr, Sep to Dec Likely to bolt if sown in November and December.
- Arid / Semi-Arid (Alice Springs): Feb to Oct Likely to bolt if sown in July, August, September and October.
- Mediterranean (Perth): all year Likely to bolt if sown in October, November and December.
Can you grow radish all year round in Cairns?
No. In the Tropical zone the planting months are Apr to Jul. Outside that window it either bolts, sulks or gets cut down by the weather. Likely to bolt if sown in July.
When should I plant Radish in Cairns?
Sow direct from April to July in the dry season. Summer sowings bolt quickly in heat and long days. Daikon types suit the tropical dry season well.
What soil temperature do Radish need?
Radish germinate best when soil temperature is between 8°C and 30°C.
How do I know when Radish are ready to harvest?
Round varieties: shoulder visible at soil level, 2-3cm diameter. Pull one to check. Summer types: harvest at 4-6 weeks before they become pithy. Winter/daikon types: harvest at 8-10 weeks when 15-25cm long.
What are the best Radish varieties for Cairns?
Recommended varieties for the Tropical zone include: White Icicle, Cherry Belle, French Breakfast, Daikon (Oriental winter radish).
What grows well with Radish?
Good companion plants for Radish include: Carrot, Parsnip, Watermelon, Nasturtium, Dwarf Beans.
Are radish salt tolerant?
Only a little. Radish 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.