RHS Growing Guides
How to grow horseradish
Our detailed growing guide will help you with each step in successfully growing Horseradish.
Getting Started
Make your own horseradish sauce from the taproots of this easy-to-grow
Horseradish produces clumps of large green leaves above its white taproots
Horseradish forms a large leafy clump, growing up to 90cm (35in) tall.
Month by Month
Jobs to do now
| J | F | M | A | M | J | J | A | S | O | N | D | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sow | ||||||||||||
| Plant | ||||||||||||
| Harvest |
Choosing
There is only one species of horseradish widely available to buy – Armoracia rusticana. The variety 'Variegata', with irregular pale cream variegation, is also available. It's slightly less vigorous than the straight species and its large cream-splashed leaves add interest to a herb garden.
What and where to buy
Horseradish is sold as plants, typically in pot sizes from 9cm (3.5in) up to 2 litres. Many garden centres and online retailers stock young plants in spring and summer. It's also sold as long pieces of root (thongs), available in spring from online veg and herb plant suppliers. Both will establish quickly and should be large enough to harvest from their second year onwards.
Seeds are occasionally available, but these take longer to form an established clump – it’s much quicker and simpler to plant roots or young plants.
Recommended Varieties
Large green-leaved horseradish forming clumps of fleshy white taproots with a fiery flavour.
Sowing
Horseradish seeds aren't widely available, so this herb is usually grown from pieces of root or young plants, which are easier and quicker options (see Planting below). But if you do track down seeds, sow them in a container outdoors in spring. It’s best not to sow in open ground, as horseradish forms deep-rooted clumps that are hard to remove. Choose a container that’s at least 30cm (12in) wide and deep, place in a warm, sunny spot, then fill with peat-free multi-purpose compost. Scatter the seeds thinly, cover lightly with compost and water well.
Planting
Grow horseradish in a large pot to stop it spreading and for easy harvesting
Planting horseradish is simple – choose a container measuring at least 30cm (12in) wide and deep, and fill with peat-free multi-purpose compost. Then plant one young plant in the centre, or up to three roots. To plant a root, make a deep hole with a dibber or trowel handle, insert the root vertically so the top is 5cm (2in) below the surface, then cover with compost and water well.
If you're happy for horseradish to spread, you can plant it in the ground. It grows well in most soil types, but roots will rot in waterlogged soil and they won't develop well in very dry conditions. Soil preparation isn't usually necessary, but if your soil is poor, mix some well-rotted organic matter into the soil you remove from your planting hole and use this to backfill after planting. Alternatively, if you’re practising no-dig, mulch the surface with well-rotted organic matter and plant directly into the mulch.
The large leaves and vigorous growth of horseradish can overwhelm smaller herbs
Plant Care
Harvest horseradish roots annually to keep plants at a manageable size
Watering
When grown in a container, horseradish will need watering during the growing season, especially in warm, dry weather. The leaves may flop if the plant gets too dry. Add enough water to keep the compost evenly moist. You can reduce watering by moving pots to a shadier spot in hot, sunny weather.
Water horseradish planted in the ground during dry spells in its first year. Once established, horseradish growing in the ground shouldn't need any additional watering.
Mulching
Horseradish grown in the ground benefits from mulching in late winter or early spring. Apply a 5–7.5cm (2–3in) layer of well-rotted organic matter, such as garden compost, around the clump. Mulching will improve your soil, help to retain moisture and suppress weeds.
Feeding
Plants in containers will benefit from an organic-based, general purpose liquid fertiliser applied every few weeks from mid-spring to late summer, or a general-purpose granular feed sprinkled on the compost in spring. Horseradish grown in the ground shouldn't need any additional feeding.
Propagating
One horseradish plant is usually enough for most needs, but you may want to make new plants to share with friends. There are a couple of easy ways to propagate horseradish.
- Simply take off pieces of root, about 15cm (6in) long, when harvesting in autumn, then pot them up (see Planting above)
- Divide established clumps in spring or autumn. Pot up divisions that have a few taproots and healthy growing points at the tops of the roots
Harvesting
Use freshly grated horseradish roots after harvesting, washing and peeling
To harvest horseradish roots, tip the plant out of its container and remove up to half of the slender white taproots. Replant the remaining roots back in the container, using fresh peat-free potting compost. If your horseradish plant is growing in the ground, simply lift what you need with a garden fork. Harvesting some of the roots annually helps to control the spread of this very vigorous plant.
Horseradish roots will add a fiery punch to many dishes. Simply peel the root and grate it to make horseradish sauce, or add it to coleslaw, salad dressings and dips. It can be used as a replacement for wasabi too. Horseradish is best used raw, as it loses much of its flavour when cooked.
Once grated, horseradish should be used quickly as it will discolour and the flavour may fade. Whole roots store well in a cool, dark, frost-free place – bundle them together in a wooden box or tray and cover with damp sand. Alternatively, store in an airtight container in the fridge for up to several months.
Fresh young leaves can also be harvested in spring and summer. They have a similar taste to the roots and can be added fresh to salads or cooked as a leafy vegetable.
Problems
Horseradish is a tough, hardy and vigorous plant that is rarely troubled by any diseases or insects. The only issue is that it can be overly vigorous, so it's best grown in a container. Horseradish can be hard to control in open ground, as the roots go very deep and growth spreads outwards. It will re-grow from any pieces of root left in the soil.
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.