University of Vermont Extension 
Department of Plant and Soil Science

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EASY-GROWING HORSERADISH
 
Dr. Leonard Perry, Extension Professor
University of Vermont

If you’re like me and like to use horseradish in cooking (seafood to me is a great excuse to use lots of cocktail sauce with horseradish), you might consider growing your own.  If you’re new to gardening, or don’t have a green thumb, also consider growing this easy root crop.  Actually, you don’t really grow this vegetable as it grows pretty much by itself.  To avoid problems, keep a few points in mind when planting horseradish in your garden.

Consider not even planting horseradish in your garden, but rather outside in its own plot.  Once established, plants can become large and spread aggressively into colonies.  Digging out roots, you are bound to miss some or leave some pieces, each of which can sprout into a new plant.  Or, you can grow it in a large container.
           
Horseradish is a hardy perennial, coming back from the roots each year, related to mustard and cabbage.  Said to be native to Russia and eastern Europe, it has been grown in northern Europe for many centuries.  It has been popular in England since the late 1600’s, and it is from there that horseradish was brought to America.

Horseradish is not fussy, growing in most soils as long as they are not constantly wet.  It grows best in full sun, but will tolerate a few hours of shade per day.  Since it is so vigorous, it doesn’t need additional encouragement from fertilizer.  Some compost worked into the soil at planting, and then composted manure spread around plants as growth starts each spring, is all that is needed.
 
You start horseradish from root cuttings (pieces of the root), not seeds.  If you know someone already growing this crop, get a piece from them.  Otherwise, you can buy roots in spring at many full service garden stores.  When buying roots, one end will be cut on a slant which is the end you place down in the soil (they like to be planted with the right side up).  If transplanting from a friend’s garden, make sure to cut the bottom of the 4- to 5-inch root cutting on a slant the same way.
           
Often you obtain horseradish roots to plant as just that, unnamed.  If they grow broad, crinkled leaves they are the common type, but if they grow narrower, smooth leaves they are the Bohemian type.  They’re also grouped by the shape of the leaf bases, type I being heart-shaped, type III being tapered, and type II being in between.  A couple of cultivars you may find are ‘Big Top’ (smooth, type I) or ‘Maliner Kren’ (crinkled, type III).
           
Unless you plan to use lots of horseradish, only a few plants should be sufficient (they are often sold in packages of 5).  Make sure soil is weeded prior to planting.  Dig a hole or trench, placing the root (slanted side down) in at a 45-degree angle so new roots can grow straight down and not get tangled.  The top, or flat end, should be one to two inches below the soil surface when you’re done.  If planting several roots, space 18- to 24-inches apart.
           
Keep the soil moist until plants start growing, and again late in the season when they are doing most of their growing.  Water during long, drought periods too.  Mulch helps control weeds and conserve soil moisture.  Tempting as it may be, don’t harvest the first year in order for plants to develop strong roots.  You can begin harvest the second fall, after the first frost.
           
To harvest, lift plants gently, loosening the soil with a garden fork.  Remove some of the smaller sideshoots to replant.  Discard roots over 3 years old as they become tough.  Cut tops off the roots to store, and use a brush to remove most of the soil.  Then store like carrots in a root cellar or cool non-freezing area in damp sand (or similar), or in perforated plastic bags in a refrigerator crisper.  They’ll usually keep for up to 3 months. 
           
To use horseradish root, wash and peel, then grind or grate and jump back to avoid being knocked over by the fumes!  Grate outdoors or in a well-ventilated area if possible.  Another method is to place peeled pieces in a grinder or blender with a small amount of water and a couple ice cubes.  Since adding vinegar or lemon juice stops the enzyme process that gives horseradish its heat and bite, adding one of these immediately will give a milder sauce.  Wait up to 3 minutes to add vinegar for a hotter sauce.  Use 2 to 3 tablespoons of vinegar, and one-half teaspoon of salt, per cup of final sauce.  Excess sauce can be frozen.  Make sure not to serve in silverware, as it will blacken in contact with horseradish.
           
In addition to adding fresh horseradish to ketchup for cocktail sauce, add horseradish to softened butter to use with meat dishes.  Add to sour cream with herbs for a vegetable dip.  More on uses can be found from the Horseradish Information Council (www.horseradish.org).  More on growing this easy crop, as well as facts and history, can be found from the International Herb Association where it was named Herb of the Year for 2011 (iherb.org).
   

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