[3] In his 1988 book Permaculture: A Designers‘ Manual, he discussed the omnipresence of spiral shapes in nature and early cultures.
The padded bottom is increasingly mixed upwards with sand to make it permeable.
[5] Seen from below, the herb spiral begins with a small pond on the south side.
This creates a moist microclimate and also reflects light and heat against the south wall to the roots of the heat-loving herbs.
[6] The transition between these zones is fluent, so that a wide range is covered by growth conditions.