The earth is the most important organ for the growth and the health of the medicinal plants. The regular addition of compost and other procedures such as application of the biodynamic preparations increase the fertility of the soil and enhance the vital processes in the earth. In order to produce good compost a lot of preparatory work is necessary. In the WALA gardens there are altogether about 50 composts. Most of them are mixed composts, that is they contain all the plant residues occurring in the garden, e.g. grass clippings, prunings etc.. In addition, while preparing the compost heap, layers of cow mature from the nearby Demeter farm "Sonnenhof" in Bad Boll are added. When the compost heap has reached a certain height it is covered with straw. In the following spring or autumn the compost is then turned for the first time.

Apart from these mixed composts, leaf and wood chipping composts are also prepared in late autumn. The leaves for this are collected in late autumn, the wood chippings come from cutting back trees and bushes.