The principle of a herb spiral is simple, but functional. A herb spiral is basically a small herb garden. It is three-dimensional and has beds in a confined, spiral shaped space, which can be used to grow various herbs.
The herb spiral, an invention of Bill Mollison's, dubbed the "co-founder of Permaculture", creates micro-climates that provide for a multitude of medicinal and culinary herbs.
Thinking in patterns, inspired by the image of a sea shell shape, Bill Mollison made a ziggurat garden that goes up in the air and down in the ground, freeing the gardener from flat patterned gardens.
“With the spiral shape had designed a varietyof micro-climates, shaded and semishaded niches here and there, and bright, hotsunny places to the west and east. It is superbly adapted for culinary herbs.You have different drainages from group to group, different heats and shade. Itis possible also to grow out the sides of it, as well as on the flat. … Itcondensed space, it reduced intercrop, cut down plant competition. Every planthas plenty of root space and plenty of climbing space.”
(Designing for Permaculture, By Bill Mollison, Pamphlet VIII, 1981)
Here’s how it works, according to Toby Hemenway:
“The herb spiral has slopes that face in all the directions of the compass. The North-facing side, which gets morning sun, will dry out earlier in the day than the west one. The soil at the bottom will stay wetter than that at the top. We’ve created an herb garden with different microclimates. So we plant accordingly, locating each herb in suitable environment. Varieties that thrive, and hot, dry climates, such as oregano, rosemary, and thyme, go on the sunny north side near the top. Parsley and chives, which prefer cooler, moister climes, find a home on the south side. Coriander, which seems to bolt in too much hot sun, can be stationed on the east side, protected from afternoon scorchings.” (adapted to our location -Nerang)
(‘GAIA’S Garden: A Guide to Home-Scales Permaculture, Toby Hemenway)
The two spiral gardens at the Edible Landscape project are about 8 linear meter coils of pathside plants formed into a roundish pattern about 1.5 meters across and mounding up about 80 cm in height, which means we can reach the central herbs without bending over very far.
The Jeans pots were filled up with coarse composted mulch, which regulates solar heat and passes it at night back to the plant. We ensure the foot of the herb spirals are facing south to reduce evaporation and retain the moisture in the lower area, where we can grow plants that love saturated soil. The base of the spiral garden has two water micro-harvest pits, filled up with composted mulch, before the jeans are set up. This guarantees a wet reservoir that the jeans fabric will move up to provide moisture for the plants’ roots.
The Jeans as pots look very attractive and right for spiral herb gardens. We took care to fill the space between the jeans, because it is very important not to leave any cavity where snakes can hide.
EdibleScapes made four zones with different soil characteristics according to exposure to the sun and drainage capacity. This provides a range of different microclimates and the perfect growing spaces for a wide variety of medicinal and culinary herbs.
This project is thanks to the generosity of Botanical Bazaar, who sponsor the presentation of the herb spiral garden at the 16th September Gold Coast Gardening Expo, before transplanting to its permanent home at the Mandala Sun Garden of the Edible Landscape Gardens site. The first 100 herbs was supplied by Mudbrick Cottage Herb farm with special discount for the spiral garden project.