Australian ecologists, David Holmgren and Bill Mollison, first coined the term permaculture in 1978, encompassing holistic methods for planning, updating and maintaining environmentally sustainable, socially just and financially viable systems. For Mollison, "Permaculture is the philosophy of working with and not against nature, after a long and thoughtful observation." In this sense, herbal spirals are an excellent exercise to begin to understand some of the concepts of this culture, as it brings together various natural functions in a single element, making it more productive and healthy.
The spiral structure promotes the creation of microclimates in a small space, enabling the cultivation of species with different requirements of water, light, and nutrients. At the top, exposure to the sun is higher, causing the substrate to become drier as it drains to the lower parts. The lower, the moister the earth becomes. In addition, there are parts more shaded and others more exposed to the sun.
For its construction, it is recommended to choose a flat, sunny and easily accessible space, preferably near where the meals are prepared. The walls can be constructed with an infinite choice of materials, all you need is creativity and the resources. Stones, bricks, logs, bamboo, or even tiles or bottles can work. It's important that the radius of the spiral is not huge so that you can easily reach all its parts at arm's length. Therefore, reserve a space between 1.00 to 1.60 meters, and at least 60 cm around it to circulate.
The first row of material is essential to shape the structure. After that, the blocks must be paired, removing some of each of the layers, to make the structure staggered. After reaching the desired height, close to 1.00 meter, the structure must be filled with soil. A good drainage system and fertilization it highly recommended. For this, consider including sand and organic fertilizers in the mixture. Then, plant the species through seedlings or seeds. The species that work well for each part of the spiral are listed below:
1. Full Sun and Dry Soil
2. Medium Shadow and Relatively Humid Soil
3. Medium Shadow and Humid Soil
As permaculture advises, it's important to observe and evaluate the behavior of each species and its relationship with others. That is, apply one of the twelve principles of permaculture: "By taking the time to engage with nature we can design solutions that suit our particular situation." - David Holmgren