1 Rhizome
Horseradish (Armoracia rusticana) is a vigorous, easy-to-grow perennial root vegetable prized for its bold, spicy root. The long, tapering roots are grated fresh to add a zesty kick to sauces, meats, and pickles. Thriving in cool to mild tropical climates, horseradish grows year after year with minimal effort, making it perfect for home gardeners. The roots reach their full potential after their second year of growth, developing their best size and flavour. Once mature, they provide a robust harvest, perfect for all your culinary creations.
While the roots are the main attraction, young horseradish leaves are also edible. They can be used sparingly in salads or cooked dishes, offering a peppery flavour to complement the root’s intensity. Just a small handful of leaves goes a long way!
Health Benefits: Horseradish is rich in vitamin C, fibre, and antioxidants, and has been traditionally used to support digestion and reduce inflammation.
Planting Tip: Horseradish is vigorous and can spread easily. Plant in a contained bed or large pot to prevent it from outgrowing other plants or taking over your garden.
In Tasmania plant in late winter to spring (August to October), once the risk of frost has passed. Plant in full sun to part shade (especially in warmer regions) in loose, free-draining, rich in organic matter with a pH of 6.0–7.5.
Place the rhizome horizontally about 2-5 cm below the soil surface, with any signs of growth pointing upward. This ensures the shoots have enough space to emerge easily and grow strong. Make sure not to plant too deeply, as this could hinder shoot development. , Plant with 40–60 cm between plants
Horseradish grows best in loose, well-drained soil enriched with compost or well-rotted manure. For pots, use a premium potting mix with added compost.
Water well after planting and keep the soil consistently moist but not soggy, especially during the first growing season.
• Too much water can cause root rot, while too little can result in thin, woody roots.
• Once established, horseradish is drought-tolerant when grown in the ground but needs more frequent watering in pots, especially in dry weather.
Apply mulch (straw, sugarcane, or lucerne) around the plant to conserve moisture and suppress weeds. Keep mulch away from the crown to prevent rotting.
Feed every 3–4 weeks with a balanced liquid fertiliser like seaweed or fish emulsion.
*Avoid high-nitrogen fertilisers or fresh chicken manure, as they promote leafy growth over root development.
Horseradish is best harvested in late autumn or winter, in the plant’s second year, when the roots have had time to fully develop their size and flavour. A sign that the plant is ready is when the leaves change from a smooth, undivided shape to a more fern-like form with serrated, finger-like segments. As they begin to yellow and die back, the roots are mature and ready to lift. In cooler regions, waiting until after the first frost can intensify the root’s pungency and give it an extra kick of flavour. However, frost is not essential - horseradish grown in frost-free climates will still develop a good, strong flavour when harvested at the right stage.
You don’t need to harvest the entire plant at once - simply dig up what you need and leave the rest in the ground to regrow the following season. Small root fragments left behind may also regrow, so it’s best to harvest gently to avoid spreading the plant where you don’t want it. After harvesting, remove the remaining leaves and stems to help the plant enter dormancy and encourage healthy regrowth. This also prevents unnecessary energy from going into flower and seed production. With yearly harvesting after the second season, horseradish will continue to produce tender, flavoursome roots for many seasons to come.
Storage:
• Freshly dug roots can be stored in the fridge for several weeks.
• Alternatively, whole roots can be stored in an airtight freezer bag and kept in the freezer for up to a year. You can also grate and freeze the roots or store them in vinegar for year-round use.
Divide horseradish every 2–3 years during winter, when the plant is not actively growing. This helps maintain root quality and control spread.
Pests & Diseases:
Horseradish is generally pest- and disease-resistant, but watch for:
• Root rot – Caused by poor drainage. Prevent by planting in well-drained soil.
• Aphids – Rinse off with water or use insecticidal soap.
• Flea beetles – Prevent by using row covers or neem oil.
• Leaf spot or rust – Remove affected leaves and improve air circulation.
Prevention: Ensure well-drained soil, avoid overhead watering, and provide proper spacing.
Companion Planting
• Good companions: Potatoes, strawberries (with proper spacing), rhubarb, asparagus, and Jerusalem artichoke.
• Avoid planting near: Beans and nightshades (e.g. tomatoes, eggplants) as they may compete for nutrients.
Toxicity & Safety:
Horseradish is safe for culinary use in small amounts. It can be quite pungent when grated, so wear gloves if you have sensitive skin. Consuming large amounts may cause mild gastrointestinal discomfort, however using it in small quantities is safe. Keep out of reach of children and pets - consult a healthcare provider if you have concerns about digestion or thyroid conditions.
Supplied as a dormant plant.