How to Grow Horseradish

Easy to grow, hard to get rid of. Plant it somewhere you have decided on.

Horseradish is a perennial grown for its root, and it is one of the very few crops where the main risk is that it does too well. Plant it once, in the wrong place, and you will be pulling it out for years.

Plant it somewhere you can contain it

It spreads from any piece of root left in the ground, and even a fragment the size of a fingernail will make a new plant. Before anything else, decide where it goes:

• A large pot or a half barrel is the simplest answer and gives perfectly good roots.
• A bottomless tub sunk into a bed works if you want it in the ground.
• A corner bounded by mown grass, which is the low-effort version. Mowing stops it escaping.

Do not put it in the middle of a vegetable bed you intend to dig.

Planting

Plant root cuttings in August, September, October. Take a pencil-thick piece of root about 20 cm long, and plant it at an angle with the thick end up and about 5 cm below the surface. Angling it makes the root easier to lift whole later.

It wants deep, loose soil to make a straight root. Stony or shallow ground gives you a forked knot that is miserable to peel.

Looking after it

Very little. Water in a dry spell, keep the weeds down while it establishes, and cut the flower stem off if it appears, since flowering takes energy from the root.

For a single clean root rather than a clump, rub off the side shoots on the upper part of the root once in midsummer. That is the traditional method and it makes a noticeable difference.

Harvest

Lift in late autumn and winter, after frost has knocked the leaves back. The flavour is strongest then. Dig the whole root out if you can, because whatever you leave is next year's plant, which is fine if you meant it and a nuisance if you did not.

Keep the best straight pieces for replanting and store the rest in damp sand in a cool place, or in the fridge wrapped, where it keeps for months.

Making horseradish sauce

The heat is made the moment you cut the root, in the same way as mustard, and it is fierce. Grate it outside or in a well-ventilated room, and keep your face out of the bowl.

Vinegar stops the reaction. Add it straight away for a mild sauce, or wait two or three minutes for a hot one, then jar it. Grated horseradish loses its heat quickly in air, so make small batches and keep them sealed and cold.

See also: How to Grow Horseradish in the Plant Library for sowing months tuned to your region.