How to grow and care for horseradish

Planting horseradish in the garden

Horseradish prefers a sunny to partially shaded spot with moist but well-drained soil. It can be invasive, as it forms vigorous spreading clumps and will re-grow from any root sections left in the ground. To stop it spreading, plant in a contained area such as a raised bed.

1. Soil preparation: Enrich the soil by digging in well-rotted garden compost or soil improver.
2. Planting: If growing from a potted plant, remove the plant from its pot and place it in the prepared soil, ensuring the root ball is fully covered. To plant horseradish roots (known as ‘thongs’) make a deep hole with a dibber and insert the root so that the top is 5cm below the surface of the soil. Cover with soil and water well.
3. Watering and mulching: Water thoroughly after planting and apply mulch around the base of the plant to retain moisture.

Planting horseradish in containers

Growing horseradish in containers keeps its vigorous growth contained, making it easier to manage in smaller gardens or patios.

1. Choosing the right pot: Use a medium to large pot at least 40 cm wide and equally deep. Ensure the pot has good drainage to prevent waterlogging.
2. Potting mix: Fill the container with peat-free multipurpose compost.
3. Planting:
   
   • If planting a potted horseradish plant, gently remove it from its nursery pot and position it centrally in the new container.
   • To plant a horseradish root (a ‘thong’), make a deep hole in the compost with a dibber and insert the root vertically, ensuring the growing tips or shoots sit about 5cm below the surface.
4. Watering: Water thoroughly. Potted horseradish needs regular watering, especially during warm weather, as pots dry out faster than garden soil. Check moisture levels frequently to ensure the soil remains consistently moist but not soggy.

How to grow horseradish from seed

Horseradish isn’t often grown from seed, as it takes much longer to produce a plant of harvestable size than when growing horseradish from roots. The seeds can be sown directly into pots or well-prepared soil outdoors between late spring and early summer, or started indoors in late winter and planted out in mid-spring.

Sow the seeds 1cm deep in well-prepared soil or pots filled with multipurpose compost. Allow 20cm between plants and 50cm between rows. Germination usually takes 1-2 weeks.

Caring for horseradish plants

Horseradish plants grown in the ground need little attention once established, except for watering in dry periods.  Water container-grown horseradish plants regularly and feed monthly with a balanced liquid fertiliser.

Harvesting horseradish

Horseradish roots are ready to harvest in late autumn or early winter after one or two growing seasons.

To harvest roots from plants in the ground, dig up a portion of the plant with its root using a garden spade. To harvest pot-grown horseradish, remove it from its pot and cut off a portion of the root, leaving at least half of the plant’s roots intact and replacing the plant in its pot.

Wash and peel the roots for use. It’s best to do this in a well-ventilated area as the pungent roots can irritate the eyes in the same way as raw onions do. Freshly grated or sliced horseradish has the strongest flavour and is perfect for sauces, mustards, and pickles.

Horseradish leaves are also edible, offering a milder flavour. Use them raw in salads or cooked as a leafy green.