When to Plant Radish in Canberra — Cold / Highland Guide
Photo: Wikimedia Commons
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. Summer, winter, and oriental types offer year-round harvesting potential across most Australian zones.
Planting Calendar
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| D | D | D | D | — | — | — | — | D | D | D | D |
S = Seed Tray T = Transplant D = Direct Sow
Current Growing Conditions
Soil temperature: 18.9°C (optimal range: 8–30°C) ✓ Ready to plant
How to Grow Radish in Cold / Highland Australia
When to Plant
Plant September-April. Too cold in winter for germination or meaningful growth. Fast-maturing varieties give the quickest return in a short season.
- 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.
- 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.
Companion plants: Lettuce, Spinach, Carrot (as trap crop for flea beetle), Peas, Nasturtium
Avoid planting near: Hyssop, Other brassicas (to reduce shared pest load)
Cold / Highland Growing Tips for Radish
Recommended Varieties
- Cherry Belle
- French Breakfast
- Sparkler
- Daikon (autumn sowing)
Key Challenges
- Short growing season
- Frost damage to young seedlings
- Slow germination in cold soil
Pro Tips
- Start early under cloches or in cold frames to extend the season
- Focus on fast varieties (25-30 day types) to maximise the number of successions
- Interplant with lettuce for a quick double harvest
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.
Common Radish Pests in Cold / Highland Zones
Organic prevention: Avoid planting brassicas in the same spot consecutively. Remove crop debris. Water regularly (flea beetles prefer dry conditions). Interplant with non-brassica crops. Trap cropping with mustard can dr
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