GROWING HORSERADISH Quick Links Planting Irrigation Fertilization Harvesting BEFORE YOU START pH: 6.0–6.7 In-row spacing: ten to twelve inches (10–12") Between rows: three feet (3') Give this hardy perennial plenty of space as it spreads readily. Eradicate all perennial weeds prior to planting. Horseradish thrives in full sun but will tolerate light shade. Horseradish performs best in deep loam or sandy loam soil types that are rich in organic matter and have good drainage. We do not recommend growing horseradish in shallow soils over hard subsoils, as the roots may become distorted or branch more, and yields may decrease in stony, shallow, or hard soils. Horseradish grows well where the growing season is long and warm, and temperatures cool significantly in the autumn. It is advantageous to have your Agricultural Extension Service perform a crop-specific soil test eight to ten (8-10) months before your planned planting date. Early identification of precisely what nutrients or amendments are needed, and how much, allows optimized application. Some amendments require time to take effect, and some are less effective when applied to the soil surface. Phosphorus and potash levels often need adjustment. PLANTING Set your roots in the early spring when the soil is workable. Dig furrows that are three to five inches (3–5") deep. Place the root pieces at a forty-fie-degree (45º) angle in the soil, with the flat (larger) end facing up and the slanted end facing down. The flat end should be one to two inches (1–2") below the soil surface. Positioning the plants in the soil at a 45-degree angle and ensuring all the tops are pointing in the same direction is crucial for vigorous establishment and growth. Fill the furrow with soil and press firmly to hold the roots in place and irrigate well. IRRIGATION Check soil moisture regularly. Roots need dry time to breathe, so irrigate two to four (2-4) times each week, depending on soil drainage and weather conditions. Keep soil moist throughout the establishment period and throughout the growing season, but do not overwater. Horseradish's most productive growth months are in late summer and early fall. To increase productivity and potential yields, we recommend irrigating horseradish during dry periods, typically in August and September (depending on location). Water plants if they wilt during hot weather, but try to irrigate just before this sign of stress. FERTILIZATION For optimum growth and efficient use of fertilizer, have crop-specific soil tests every two to three (2-3) years. Horseradish does not require a lot of fertilization. Fertilize in spring with five pounds (5 lbs.) of 10-10-10 per 100 square feet or apply nutrients according to soil test recommendations. HARVESTING AND STORAGE We do not recommend harvesting in the planting year to allow the plants to become well established. In the subsequent years, you may harvest horseradish roots anytime from midsummer on, but for the best flavor, wait until late fall or until after the first frosts when the foliage has died back. Dig or loosen the soil around the roots and pull them out of the soil. Take the large, main root, and as much of the secondary root system as possible. The main root is the largest and most valuable for the market. Smaller, side roots that are three-quarters of an inch (¾") in diameter and about eight inches (8") or longer can be replanted in a new bed to provide your next year's crop. If not harvested, divide the roots every year or two (2). Scrub the roots under running water and dry thoroughly. Store additional roots in a dark, cold storage at 30–32°F with a ninety to ninety eight percent (90–98%) humidity for up to one (1) year. Roots may become green when exposed to light.
