How to Grow Horseradish in Your Garden

Horseradish, part of the Brassicaceae plant family, is a hardy perennial root vegetable with a long growing season. Horseradish produces a mustard oil that, when grated or cut, can irritate the sinuses and make your eyes water. However, horseradish contains considerable nutrients like vitamin C, potassium, and calcium.

Horseradish is one of the easiest vegetables to grow in your home garden, due to its flexibility. Horseradish plants thrive in full sun or partial shade and can grow in most soil types. Plant horseradish in early spring, two to three weeks before the last frost date in your region.

Here’s how to start growing horseradish in your herb or vegetable garden:

• Buy horseradish sets. Horseradish is usually grown by planting small root pieces (also known as horseradish sets) directly into the ground soil. Horseradish sets are available for purchase at most supermarkets, farmer’s markets, and nurseries.
• Choose the soil. Horseradish can be grown in most soil types but it likes slightly acidic and loamy conditions, with a soil pH between 6.0 and 7.5.
• Pick a grow site. Keep your horseradish planting site at least one and a half to two feet away from other plants to leave enough room for the roots to develop without interfering with your other crops. Be sure to plant horseradish near full sun or with partial shade.
• Make room for roots. Horseradish taproots grow deeply and can use as much as a foot of depth (or more, if left unattended for too long). Dig a trench around three to four inches deep in unobstructed, loose soil. The trench should also be wide enough for your horseradish root to lay at a 45-degree angle, tapered and exposed root side down. Cover with topsoil.
• Companion plant. Rhubarb, sweet potatoes, and asparagus all make good companions for your horseradish plant, but don’t plant too closely. Horseradish roots need room to spread, and may compete for resources or destroy the more fragile roots of nearby fruits and veggies.

Horseradish is a low-maintenance plant that can tolerate frost and has very few garden foes. However, it’s still important to tend to your horseradish plant’s essential needs:

• Water weekly. Horseradish roots can retain moisture well, so they don’t need frequent watering. Water horseradish roots once or twice a week, using just enough water to keep the soil slightly moist. Overwatering can kill your horseradish plant.
• Fertilize if necessary. Use a low-nitrogen, high-phosphate fertilizer, if your soil lacks the proper nutrients.
• Prune and weed. Trim away all but three or four of the tall leaves surrounding the crown of your horseradish plant. The tall leaves are called “suckers,” and can grow up to four feet long. Suckers should be trimmed back when they’re around eight inches to stop roots from undesirable spreading or becoming irregularly shaped.
• Check for pests. Horseradish is affected by flea beetles and cabbage worms, so treat your plants with an organic insecticide or keep near companion planting spots for beneficial insects that feed on these garden pests.

Horseradish takes one year to reach maturity, after the initial planting. Horseradish planted in early spring will be ready to harvest by early spring of the following year.

Horseradish takes between 140 and 160 days to harvest. Horseradish develops well during the late summer months, so even if enough time has passed, avoid harvesting your horseradish until late fall or early winter. In colder climates, harvest horseradish before the ground freezes.

When harvesting horseradish, loosen the soil around the plant. You can use a garden shovel or garden fork to carefully dig up the horseradish roots, or use your hands to pull up the entire root system. Horseradish roots grow from other horseradish roots, so be careful not to sever or cut any pieces off your plant when removing it, as it could lead to unwanted growth of new plants.

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