Choosing the Right Environment Burdock is a biennial plant that grows in USDA zones 2 through 10. It prefers loamy soil and adequate fertilization. Burdock can grow in full sun to partial shade. Sowing Seeds Directly sow burdock seeds in the spring when the soil can be prepared. Sow seeds 2? apart, 3/4? deep, in rows 24? apart. Thin to 2-3? apart. Soil Preparation Burdock requires a deep, well-drained soil to produce quality roots. Prepare the soil by weeding it thoroughly, digging it over deeply to loosen the soil, and adding aged animal manure or compost. Organic matter can be dug into heavy soil to lighten it so roots can grow freely. Watering Consistent watering is key to developing robust, sizable roots. Ensure the soil stays well-hydrated, but be cautious not to overwater, which may lead to root rot. Harvesting Burdock roots are typically harvest-ready 90-120 days after planting. Harvest the roots either in the first autumn or the second spring year. The leaves can be picked at your convenience. By following these burdock planting instructions, you can successfully grow this versatile and nutritious herb in your garden.