How to harvest horseradish

How to Grow and Store Horseradish

Barry McMillin says you can grow horseradish yourself.

You can grow horseradish in a kitchen garden, says commercial horseradish grower Barry McMillin, who occasionally hears from gardeners who want a couple of plants to “mess around with in the yard.”

One or two horseradish plants will produce enough for most families. Try our tips for planting, harvesting and storing these pungent roots.

Planting and Growing Horseradish

Plant horseradish root pieces, called “sets,” in the fall or early spring. Look for sets that are about as big around as your finger and 12” to 18” long.

Place the sets horizontally in deeply tilled soil, with the large end slightly higher than the small end, and cover them 6” to 8” deep. You’ll wind up with a ridge one to two feet across.

After the leaves sprout, fertilize the plants with well-rotted compost or 10-10-10.

The growing plants will form crowns with multiple shoots above ground. Meanwhile, under the soil, the original set will increase in diameter and form side roots. For best results, you’ll want to encourage the original set to grow as large as possible, so you’ll need to “sucker” or “lift” the plants.

To “sucker” the horseradish, remove all but one or two leaf shoots at the head, or big end, of the original set.

To “lift” the plants, use a hoe to dig into the ridge and gently raise the crown end of the original set. Your goal is to break the roots at the crown, so roots form at the tail end instead. Do this early in the growing season and again halfway through.

No matter which method you use, the original set should now grow into a one to two pound root by harvest time.

Once a freeze kills the leaves, you can start harvesting. Dig up the original root and as many of the secondary roots as desired. Save some to replant next year.

Wrap the harvested, unwashed pieces in plastic and store them in the refrigerator. They should last for months.

You can keep harvesting through the winter and into the following spring, anytime the ground isn’t frozen. Just be aware that if you break off side roots, they’ll grow into new plants. You may end up with more than you need.

Processing Horseradish

To process the horseradish, peel and dice the root pieces. Grind them in a blender with a little water and ice, until you have the consistency you want.

Add two or three tablespoons of white vinegar and a half-teaspoon of salt or table sugar for extra flavor. (Don’t use cider vinegar.) For a milder sauce, add the vinegar immediately after grinding, to inhibit the enzyme activity that causes the fiery taste.

To make a hotter sauce, grind the roots and wait several minutes before adding the vinegar.

Pack the sauce in clean, tightly sealed jars and store in the refrigerator or freezer.

McMillin likes horseradish on everything, including eggs, salads and sandwiches, but warns that the roots are pretty powerful when you grate or grind them, and you’ll shed plenty of tears preparing your own horseradish at home.

“It’s a lot easier to buy it in a jar than to grow it,” he chuckles.

Read more about the commercial horseradish harvest in the full story, “Horseradish is a Crop With Punch” >>

Best Ways to Store Horseradish Root

Growing for Best Storage

Healthy, well-grown horseradish will store better. Although it tolerates poor soil and part shade, you’ll have bigger roots with fertile, well-drained soil and full sun. Adequate moisture in the growing period means the roots will go into storage with their cells plumped up and be less likely to shrivel. It’s particularly important not to short plants on water in late summer.

Varieties of Horseradish

The horseradish variety you choose doesn’t generally affect storage quality, but may affect taste. Here are some options:

  • Maliner Kren – root quality is high, although this variety is slightly more subject to diseases.
  • Bohemian Types – these have slightly smaller roots and vary in disease resistance.
  • Variegata – the leaves are splashed with white, which makes for an ornamental plant.
  • Wasabi – a different species than other varieties, you store and use the rhizome rather than the roots.

How Harvest Affects Storage

It’s best to harvest after frost has killed the tops. Horseradish harvested too early or late may not be well grown or may be harder to get out of the ground because it is so big. When harvesting, try not to cut or break roots, which can encourage mold in storage. Don’t harvest in spring once the plant has started to regrow.

Storing Roots

Roots generally store well in a moist, cold environment such as the refrigerator. A plastic bag with a damp paper towel in the bottom is ideal. They can also be stored in a root cellar if adequate moisture is supplied. It doesn’t matter whether you’re storing them to eat or grow, as these methods work well for both purposes.

Storing Horseradish as a Condiment

Horseradish will be most peppery if grated immediately prior to use. However, you can grate it, add a little salt and a teaspoon or two of vinegar and store in the refrigerator for two weeks. The prepared condiment can also be mixed with mayonnaise or sour cream and stored for two weeks. However, you’ll lose flavor with longer storage.

Garden Storage

Horseradish can be stored right in the garden. Simply dig the roots as you need them. Mulch well in cold climates or the ground may freeze too hard to dig. If you’ve grown your horseradish as an annual, you can dig and trim the roots, then store in pits in the ground, surrounded by damp sawdust.

I am trying to find out when to harvest horseradish. I have had it growing for several years, but have never harvested it. I assume all I have to do is dig it up and let it dry before using.

Horseradish is actually a fairly easy herb to grow; all you need are deep, loose soil, a temperate climate (Northern U.S. and high altitudes), full sun and patience. It usually takes about 12 months for the roots to mature to a harvestable size, which is 1 inch or larger in diameter. That being said, don’t allow it to grow for more than a year as it will become tough and unpleasant tasting.

The best time to harvest horseradish is when the plants are dormant. This can be done in the early spring just as the crown is showing green or in fall after a killing frost. Always wear gloves when working with horseradish because the roots can cause skin irritation.

After digging the roots you can replant any unused portions such as side shoots or the crown for more horseradish later!

Rather than drying horseradish, the roots should be ground immediately after harvesting from the garden. And because they are so pungent this activity is best done outdoors or in a room with open windows.

Simply wash and peel the roots and chop them into chunks. Place the horseradish chunks in a food processor and process until the desired consistency is reached, the finer the texture the hotter the flavor. A solution of equal parts water and vinegar should be added to the horseradish to stop the heat producing enzymes. The rule of thumb is to add the solution immediately for a mild horseradish or wait 3 minutes for a hot horseradish.

Horseradish can be stored in jars for about one month or in the freezer indefinitely.

Horseradish: the best plant that you never thought about growing. Everybody knows that horseradish contains the compound allyl isothiocyanate and that it makes a great addition to a roast beef sandwich or bowl of cereal…but you might not know how easy and fun it is to grow!

A few horseradish facts:

  • It is in the Brassica plant family, meaning that it is related to broccoli and kale.

  • It is a perennial (meaning if you plant it once, it will grow back every year). It is generally regarded as a tenacious perennial, meaning that it can be difficult to extricate once planted in the garden. If you aren’t sure you want to keep it around in the long term, try planting it in a large container!

  • Collinsville, Illinois is the Horseradish Capital of the World.

Planting Instructions:

Horseradish is usually planted from a root cutting. You can order horseradish roots from many seed companies (including Johnny’s). If you order this winter, they will likely be shipped in spring, which is the best time for planting. Once the roots arrive:

1. Determine an appropriate space for the plant. It prefers full sun and produces beautiful, large rounded leaves that look great as a garden border. Remember to choose a site that can be devoted to this spreading plant and that can be dug up once a year to harvest roots.

2. Prepare the bed space by loosening the soil and adding amendments. Horseradish can thrive in many soil types but will benefit from the addition of compost and a source of potassium (greensand, wood ashes, or a basic organic fertilizer).

3. Plant the roots about 2-3” deep and 12” apart.

4. Plants don’t require heavy irrigation but will benefit from occasional watering.

Harvesting Instructions:

1. Standard practice is to plant the root in spring and wait at least 1 year for harvesting. A year after your first planting, you can dig up the plant, divide out the new, tender roots to eat and replant a few healthy roots to continue growing. Many people think that fall is the best time to harvest, so it is possible to wait until the second fall to harvest (1.5 years after planting).

2. If you let the plant go several years without harvesting, it can start to spread. If this happens, dig up sections of the plant, harvest the newer, tender roots and dispose of the older, woody roots. Be careful how you dispose of the roots as they can repopulate in a compost pile and spread across the garden. It is better to place them in a municipal yard waste bin or burn them if necessary.

Preparation Instructions:

1. A newly harvested root will probably not be incredibly pungent…until you start to chop or grate it! It is recommend that you prepare horseradish sauce outdoors or in a well-ventilated room.

2. Once you begin to make a recipe, it is important to complete the process relatively quickly because the active enzymes are short-lived. Combining the root with vinegar helps stabilize the enzymes and preserve their taste. A grated, un-vinegared root will quickly discolor and lose its potency.

It is easy and quick to make a horseradish sauce in a food-processor:

1 Cup fresh horseradish root

1 Tbsp vinegar

2 – 4 Tbsp water

1 tsp salt

1. Peel the roots and chop into 1-2” pieces

2. Add all ingredients to the food processor and blend until consistent.

3. Place in refrigerator and eat within a few weeks.

horseradish root

I love this time of year. The air is cool, the earth is damp, and there are still a few edibles in the garden. Early fall means that it is time to harvest one of my favorite vegetables. Yes, it is horseradish season!

Horseradish (Amoracia rusticana) is a perennial that is in the Brassicaceae family. This is the same family that includes cabbage, kohlrabi, brussels sprouts, and mustard. Since it is a perennial, you do not have to replant it every year like cabbage. Simply leave a few horseradish roots in the ground after each harvest and you will be blessed with horseradish for years to come. Please note that this plant is hardy in USDA zones 3 – 9.

horseradish plant

This particular vegetable is grown specifically for its very pungent root. As the season progresses, it develops more flavor. My mom who raised horseradish and whose parents raised horseradish always said, “You only harvest horseradish in a month that has an ‘r’ in it”. For her, that meant waiting until early fall with October and November being the primary months of harvest.

To test this out, I harvested some roots in May from a crop that I planted two years prior. After washing and peeling the root, there was a faint aroma, but not the harsh note that I was expecting. I grated the root and added it to some sour cream (a favorite way of enjoying it). I tried it on a baked potato and the flavor was so mild, the horseradish was barely detectable. To continue with testing, I harvested in the summer and resulting condiment had a more pronounced flavor.

But if you truly love the full depth of what horseradish can be, wait until it is no longer actively growing (which means fall) and you have already had a frost. This year, October was my harvest month.

digging horseradish roots

If you are worried about harvesting before a frost, don’t. Horseradish can survive temperatures to -20F. But with a fall harvest, your main concern should be harvesting before the ground freezes. If you wait too long and the ground does freeze, you can simply wait to harvest the following year in early spring before the plant begins to actively grow (think February through April).

To harvest horseradish, make sure the soil is slightly damp (not wet) around the roots. It will make harvesting easier compared to digging in a dry, hard packed soil. Use a digging fork (just like what you would use to harvest potatoes) and start digging about 12″ away from the plant. At this point you are loosening the soil and trying to determine which way the primary roots have grown. For the record, it is not always straight down. Continue to loosen the soil with the digging fork until you are able to get the fork under a large root. Gently lift the fork, trying to prevent the root from breaking in half. This is not always avoidable, but try to get as much of the root as possible.

After collecting the roots, wash them off. The easiest method I have found is to rinse them off with a garden hose. Once the roots are clean, pat them dry with a cloth.

rinsed horseradish roots

Now you can either store them for later use or peel them to use now. If you choose to store them, place damp (not wet) sand in a large, plastic container with a lid. Bury the roots individually with a layer of sand between them. After that, cover the container with the lid and store in a cool location like a crawl space or basement. Horseradish stored this way will last for several months.

You can also store unpeeled horseradish by wrapping them in paper towels and them placing them in a perforated plastic bag (like the ones grapes come in at the grocery store or you can simply poke holes in a regular plastic bag). Once in the bag, you can store them in the vegetable bin of the refrigerator for at least a month according to Oregon State University.

Harvesting horseradish is quite simple. Treat it like a potato using a digging fork and be sure to harvest late in the season, waiting until you have at least had a first frost. Clean and store the horseradish and you will be able to enjoy it for months to come!

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