Quick facts
- Before planting horseradish, spade or rototill the soil to a depth of 8 to 10 inches.
- Plant root cuttings, sometimes called "sets," in early spring as soon as the soil is workable.
- Weed control is especially important early in the season when the plants are relatively small.
- To grow high-quality horseradish, lift and strip the roots twice.
- The horseradish flea beetle is a serious pest on horseradish foliage.
- Delay fall harvest until late October or early November, or just before the ground freezes.
Horseradish, Armoracia rusticana, is a large-leaved, hardy European perennial herb that has been a culinary favorite for more than 3,000 years.
This fiery herb thrives in temperate climates and in the cool, high altitudes of tropical countries. Horseradish grows best in deep, rich, moist loamy soil, in a sunny location. Roots become malformed and yields are less on hard, shallow, stony soils.
Soil fertility and preparation
- Before planting horseradish, spade, or rototill the soil to a depth of 8 to 10 inches.
- Turn under or mix in generous amounts of well-decayed compost or other organic material.
- Incorporate a complete garden fertilizer (10-10-10) at a rate of one pound per 100 square feet or a large amount of well-decayed manure into the soil.
- Fresh or partly fresh manure used before planting will cause excessive top growth and forked roots.
- Let the worked-up soil settle a few days before planting.
Planting root cuttings
- Plant root cuttings, sometimes called "sets," in early spring as soon as the soil is workable.
- Space the sets one foot apart, setting them vertically or at a 45-degree angle.
- If angled, make sure that the tops point along the rows in the same direction. This makes cultivating easier.
- Cover the sets with two to three inches of soil.
How to keep your horseradish healthy and productive
- Weed control is especially important early in the season when the plants are relatively small.
- It is best to cultivate in the same direction that you planted the sets.
- Mulch around each plant with organic material such as compost or leaves. It will benefit the plants by retaining moisture in the soil, keeping the soil cooler and controlling weeds.
- To grow high-quality horseradish, lift and strip the roots twice.
- Do it first when the biggest leaves are 8 to 10 inches long and again six weeks later.
- To lift and strip, carefully remove the soil from around the upper ends of the main root. Leave roots at the lower end of the set undisturbed.
- Raise the crown and remove all but the best sprout or crown of leaves.
- Rub off all small roots from the crown and sides of the main root, leaving only those at the bottom. Return the set to its original position and replace the soil.
Horseradish grows the most during late summer and early autumn. For this reason, delay fall harvest until late October or early November, or just before the ground freezes.
Harvest by digging a trench 12 to 24 inches deep along one side of the row. Working from the opposite side of the row with a shovel or spading fork, dig the roots. Use the tops as a handle for pulling them laterally from the soil.
Trim the green tops so there is only one inch left. Trim off side and bottom roots. Save roots that are eight inches and longer for next spring's planting stock. Cut the roots squarely across at the top and slope towards the bottom. This will make it easier to know which end to set upright at planting time.
Tie cleaned root cuttings in small bundles and place them in moist sand. Overwinter horseradish in a root cellar or basement that stays between 32 and 40 degrees Fahrenheit during the winter. Do not expose the roots to light otherwise they become green.
If you cannot have the right storage and temperature conditions, harvest horseradish in spring rather than fall. Dig the roots as soon as new growth starts to appear in spring. Replant lateral roots for next spring's crop. Roots left in the ground for two growing seasons become stringy and woody.
Store horseradish roots for fresh grinding in dark plastic wrapping in the refrigerator. Protect the roots from light to prevent them from turning green.
The most common way to prepare horseradish for table use is to peel or scrape the roots. Grate the root directly into white wine vinegar or distilled vinegar. Avoid using cider vinegar, as it causes discoloration in the grated horseradish within a rather short time. Depending on your preference, you can slightly dilute the vinegar.
Bottle the horseradish and cap the containers as soon as possible after grating. Refrigerate at all times to preserve the pungent flavor. Freshly grated horseradish will keep only for a few weeks. Then prepare a fresh supply.
You can also dry horseradish, ground it into a powder and put it up in bottles in a dry form. Dried horseradish will keep much longer than the freshly grated product, but is not as high quality.
Managing pests, diseases and disorders
Many things can affect horseradish roots and leaves. Changes in physical appearance and plant health can be caused by the environment, plant diseases, insects and wildlife. In order to address what you’re seeing, it is important to make a correct diagnosis.
You can find additional help identifying common pest problems by using the online diagnostic tools or by sending a sample to the UMN Plant Disease Diagnostic Clinic. You can use Ask a Master Gardener to share pictures and get input.
Insects
Flea beetles can cause serious damage to horseradish leaves.
Diseases
Horseradish is susceptible to a variety of root rots.
- Start with disease-free cuttings when starting a new horseradish planting.
- Rotate the horseradish planting site, making sure to not plant in the same place more often than every three to four years.
Reviewed in 2022