Horseradish will be ready to harvest after one year in your garden. Does best in cool, moist, fertile soil. Plant roots, with the thick end up (upright or horizontal), outdoors in the spring as soon as the soil can be worked. Place roots 18" apart. Horseradish is a perennial, but many gardeners replant every 3-5 years, as old roots tend to get woody. We cannot ship horseradish to AK, HI.