Asparagus crowns are the root systems of asparagus plants that are two years old. They are grown for the purposes of selling at the crown stage, which is much faster than starting from seed. They are very cold hardy, but they need to be planted soon after they are delivered. If they are delivered to a place where planting is impossible due to snow or frozen soil, plant them in a large container, in soil, and keep them in a cold but protected place like a garage or garden shed.
Asparagus is a perennial plant that will produce for ten years or more from the initial planting. Soil preparation is vital to long term productivity. Dig the planting area deeply and work in a large amount of organic matter in the form of compost or well rotted manure. Add a generous amount of Glacial Rock Dust to supply mineral content. In a raised bed, think in terms of dedicating five or more years of nutrients to the plants that will develop.
Spacing for asparagus crowns requires a minimum of 45-60cm (18-24") between plants. For farms, plant the rows 1.5m (5') apart.