Herb spirals are a kind of raised garden bed popular in permaculture landscape design. A hard material (bricks, stones, concrete, pavers, etc.) is used to create the structure ("shell") of the spiral, which is then filled with soil. Choice of particular herb species should meet the requirements of the site, and their placement within the spiral should be determined by the particular plants' needs. Plants which require more sun exposure and good soil drainage should be placed toward the pinnacle of the spiral. Because it makes use of vertical space, an herb spiral may be appropriate for sites with limited space. If the spiral will contain culinary herbs, it should be placed within zone 1, near the kitchen. The popularity of herb spirals as an introductory design for permaculture beginners is probably due to these various design considerations. This design concept may have originated at the Findhorn community in Scotland.