When to Plant Horseradish in Cairns, Tropical Guide

Sow May to June. Right now in September it is out of season. The next sowing month is May.

Published · Last reviewed · By Garden Buddy
Growing advice is reviewed by hand. Planting dates, current conditions and prices on this page update daily.

This Horseradish 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.

Horseradish

Photo: Wikimedia Commons

Horseradish is a robust, hardy perennial grown for its pungent root. Once established, it is almost impossible to eradicate. A feature or a bug depending on your perspective. Best suited to temperate and cool climates where cold winters develop the best-flavoured roots. Extremely low maintenance but must be contained or it will take over the garden.

Planting Calendar for Tropical

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
- - - - D D - - - - - -

S = Seed Tray   T = Transplant   D = Direct Sow

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Current Growing Conditions

Soil temperature: 21.4°C (optimal range: 10–25°C) ✓ Ready to plant

Modelled from Open-Meteo forecast (Cairns), not a live sensor.

How to Grow Horseradish in Tropical Australia

When to Plant

Horseradish requires cold winters to develop pungent roots and enter dormancy. Tropical zones do not provide this. Grow wasabi or galangal as alternatives.

Soil
Deep, loose, well-drained soil enriched with organic matter. Best roots form in sandy loam or loam dug to at least 30cm depth. Tolerates a wide range of soils but heavy clay produces misshapen roots. Remove stones.
pH Range
6.0-7.5
Sunlight
Full sun (6+ hours). Tolerates partial shade but root development is reduced.
Spacing
40cm apart, 60cm between rows
Watering
Moderate water needs. Water deeply once per week during active growth. Drought tolerant once established but consistent moisture produces the best roots. Reduce watering in winter when dormant.

Companion plants: Potato, Fruit trees, Grape vines

Avoid planting near: Other brassicas (shares diseases)

Tropical Growing Tips for Horseradish

Recommended Varieties

  • Not recommended for tropical zones

Key Challenges

  • No winter dormancy period
  • Roots lack pungency without cold
  • May not survive wet season

Pro Tips

  • Horseradish is not suited to tropical zones. It needs cold to trigger root starch storage
  • Consider Japanese horseradish (wasabi) or galangal as tropical alternatives
  • If growing purely for leaves, it may survive but root quality will be poor

Harvesting Horseradish

When ready: Harvest after the first frosts of autumn/winter, or at least 16-24 weeks after planting. Roots should be at least 30cm long and 3-5cm diameter at the crown. Leaves may have died back partially in cold climates.

How to harvest: Dig deeply alongside the root with a garden fork. Roots can go 60cm+ deep. Lever out carefully. Any root fragment left in soil WILL regrow, so be thorough if you want to contain the plant. Snap off side roots for replanting or discard in bin (not compost).

Where to next

Also worth sowing in the tropical zone this September: Lemongrass, Ginger, Cucumber and Basil.

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Common Questions About Horseradish

When do you plant horseradish in Australia?

It depends on your climate zone, not the calendar month alone. Planting months by zone:

Does horseradish grow all year round in Cairns?

No. In the Tropical zone the planting months are May to Jun. Outside that window it either bolts, sulks or gets cut down by the weather.

Which zone am I in?

Type your postcode into the box under the heading and the page 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.