Herb spirals are a permaculture design installation that allows you to grow a diverse array of herbs on a single, unique structure that’s great for adding some functional, whimsy into your garden space.
Photo attributed to amberdc at Flickr.com
Herb spirals work by creating micro-climates along various spots of the spiral that create ideal growing conditions for Rosemary, Thyme, Lemongrass, Tarragon, Basil, Mint and everything in between.
The first step to building an herb spiral of your very own is choosing a location. In order to get the most out of your herb spiral, it is recommended that it be constructed as close to your kitchen as possible, as close proximity will allow easy, quick access even in inclement weather. Secondly, a majority of common cuisine herbs prefer a good bit of sunlight, so areas away from walls and stands of trees are best. Finally, a flat area at least 2 meters in diameter will allow ample space for at least a couple twists in the spiral. Smaller spirals may not allow for enough variety in micro-climates and larger spirals will make harvesting herbs in the center difficult.
Next up is prepping and laying out the site for the installation. The “pond” or the lip of the spiral that meets the ground should be facing south. This will help you plant according to the sun, shade, and moisture requirements of each herb. If starting an herb spiral on an existing lawn, the grass will need to be covered to prevent it invading your spiral. This can be accomplished by laying wet cardboard on top of the site, with the added benefit of adding organic matter to your soil. The following diagram illustrates a basic form that can assist in the layout of your herb spiral.
Photo attributed to Lamassu Design
Now, for the fun part! Building the wall structure of your herb spiral provides you with several material options. Anything from glass bottles and rubble to bricks and river stone can be used. The first layer should be roughly four inches high as this will keep the soil in place, and the wall should be gradually scaled up as it approaches the center of the spiral, with final wall portion being anywhere from 2.5 to 4 feet tall, depending on your personal preference. Spare materials can be used to fill the bottom of the spiral to minimize soil/compost costs. All that remains is filling the spiral with nutrient-rich soil, planting your favorite herbs, and enjoying freshly-picked seasonings year round.