How to grow horseradish
Fiery horseradish is so easy to grow that this useful perennial can take over the garden so keep it in a pot! While you can bandicoot roots from an established plant year-round, horseradish will be hotter when harvested in late autumn, winter and early spring as cooler temperatures promote the formation of the compounds which give it its punchy taste.
SOW AND GROW
Plant root cuttings: March to September in warm areas; March to April and August to September in cooler areas Position: Full sun, six or more hours a day Harvest: 26 – 52 weeks Good for pots
For best results, plant horseradish from March to September, as it doesn’t like it too hot, but really you can get away with planting it any time the ground is not frozen. Horseradish is easy-peasy to propagate from a division or a root cutting. In fact, plant any part of it and it’s likely to come away!
If you don’t know anyone with a plant you can pinch a root or a cutting from, then look for it in the herbs section at the garden centre or buy a piece of root at a farmers market and plant it.
Because of its semi-invasive tendencies, it’s a good idea to confine it in a pot, although make it a decent sized pot and keep it in a spot which offers afternoon shade to avoid heat stress, or sink the entire pot into the ground to help keep it cool. In a pot, you can space as closely as 5cm apart. When transplanting seedlings, make sure to put the small bulb and roots below the soil, leaving the green stem and any foliage sticking up.
Really, just plant it! Few plants are as easy to grow as horseradish, or as hardy (established plants will easily survive snow and hard frost). It does take a while to produce though, needing up to a year in the ground before the roots can be harvested.
Give horseradish a sunny spot, with deep, moisture-retentive soil.
Water every now and again in dry spells and mulch around the plants to conserve soil moisture.
As winter approaches, the foliage dies off and it enters dormancy. Unless it’s clearly labelled, plants can be very hard to locate again until spring, by which time they’ll likely have spread.
So harvest horseradish quite brutally while the foliage persists. Either dig up clumps or pull individual roots when the soil is damp. Trim and clean the roots, then dry and freeze.
There are two types of horseradish available in New Zealand, common horseradish which has broad, crinkled leaves and good fleshy roots, and hard-tofind ‘Bohemian’ which has narrower, smoother leaves but also thinner and lower quality roots.
Really, this crop is almost trouble-free, although the foliage of newly planted plants can be attractive to white butterfly caterpillars (although they seem to ignore well established plants).