Tufa Garden

Most tuff gardens are essentially collection gardens, as it is not the geographical location but the substrate that defines the garden. Due to its porous surface, tuff is particularly suitable for dwarf plants. There are two fundamentally different types of tuff. On the one hand, there is pyroclastic tuff, which is of volcanic origin and is also frequently used as a building material. On the other hand, there is the calcareous tuff used here in the garden. This is formed when limestone is deposited in springs, trapping plant remains and air in the process. Depending on its age and how it has been stored, tuff can be porous, soft or harder. Calcareous tuffs are alkaline, with a pH value greater than 7, whilst pyroclastic tuff is neutral or slightly acidic.

Gardening challenges and tips

A tuff stone garden is demanding in terms of both construction and maintenance. Although tuff is easy to work with, as it can be sawn, drilled or broken, it is challenging to arrange the stones harmoniously and create suitable habitats for the slow-growing plants. This requires manual dexterity, precise knowledge of the plants’ needs and a good sense of how to create suitable small spaces. A tuff stone garden is planted as the stones are laid and should be weeded regularly so that the small-growing species are not crowded out. Thus, the tuff stone garden is an extremely interesting, but also demanding, garden.

What is the pH value?

The pH value is a measure of the acidic or alkaline nature of an aqueous solution. It ranges from very acidic (pH = 1) to very alkaline (pH = 14), with 7 being neutral and corresponding to the pH value of pure water. The availability of nutrients varies depending on the soil’s pH value. This affects the occurrence and growth of plants. Acidic habitats include, for example, raised bogs (pH = 3–4), whilst calcareous marl is alkaline (pH = 9–10).