by Charley MacMartin
Participants in our stone wall workshops often ask about a simple stone feature to enhance a kitchen garden. Herb spirals top the list. An herb spiral is essentially a stone wall that twists in on itself, growing higher and higher towards the center of the spiral. The result is a uniquely styled raised bed that offers a range of soil depths and planting possibilities.
The design of an herb spiral is simple. To begin, mark out the full size of the circle or oblong space that the spiral will fill. Clear the area and if you’d like to increase the drainage in the area, remove up to six inches of soil and replace with a crushed gravel base. How much stone you’ll need for the spiraling wall depends, of course, on how large the spiral you plan. For example, a spiral can be as small as a circle four feet in diameter. That’s a good size for a children’s garden so small arms can reach into the center of the planted area. On the other hand, an herb spiral can be a focal point at the center of a larger garden. Ideally, the stone you use is from your area. That cuts down on costs and reduces the amount of fossil fuels needed to create your garden. Also, as you discover more stone over your years of gardening, you can add to your spiral’s height and length.
When finished, your wall will be approximately twenty-four to thirty inches tall at the center, spiraling down to 6 inches at the outside, or tail, of the spiral. Fill the spiral with a mixture of compost and topsoil, creating a bed that is deep and well-drained at the center and shallower at the tail. This varying depth allows for a range of plants in a single bed. For example, rosemary, thyme and other herbs that want well-drained conditions will be happy at the center while mint and plants that can tolerate ‘wet feet’ will thrive at the tail. Another possibility is to devote the entire spiral to a single crop, like strawberries. Larger spirals in a sunny location can be a home for cut flowers as well.
But how ever large and how ever planted, the chief joy of an herb spiral will be you have created something of lasting beauty and function for your garden.
Charley MacMartin builds stone walls in Vermont using traditional dry-stone walling methods. To see his stone walls, go to: www.queencitysoilandstone.com