Simply piling up gravel and rocks and placing mountain plants in between doesn't make a rock garden. In order for the mini mountain world to actually survive, bloom and thrive for more than just one season, some preparation is required. The subsoil of the rock garden in particular must be carefully designed and layered.
How do I prepare the substrate for a rock garden?
To prepare the subsoil of a rock garden, remove weeds and root weeds, excavate the soil by approx. 40 cm, lay out a weed fleece and a 5 cm thick layer of gravel or chippings. Then lay a drainage pipe and cover it with another 5 cm of gravel or chippings and finally with soil.
Preparing the rock garden substrate – This is how it works
The subsoil primarily determines the success or failure of the rock garden. To ensure that waterlogging does not form, that the plants receive the soil that meets their needs and that the right living environment is created, it is best to first go into the depths.
Fight root weeds and eliminate unpleasant surprises
Before you can really get started, you first have to clear the area intended for the rock garden from weeds. In particular, root weeds such as thistles, morning glories, couch grass, sorrel, field horsetail and groundweed should be permanently removed - this only works by weeding and digging up. Other unpleasant surprises such as buried building rubble or even garbage should also be completely removed.
Remove the floor and replace it if necessary
In general, it makes sense to excavate heavy and compacted soil in particular, i.e. H. it must be removed. How much soil you want to remove depends on the actual condition of the soil - around 40 centimeters is ideal. If the mini-mountain is to be created on a given slope, dig a trench about 30 centimeters deep at the base of the slope, the side wall of which is in line with the slope and perpendicular to the slope on the opposite side.
Create drainage
A weed fleece is now placed on this dug-out surface, on which you lay a layer of gravel or chippings about five centimeters thick. This forms the base for the drainage pipe, which is intended to prevent waterlogging. So-called Drain-Flex pipes (€17.00 on Amazon) with a diameter of 65 to 80 centimeters are well suited for this purpose. At the deepest point, the pipe must have an outlet that either simply runs outside, into a sewer connection or into a seepage shaft. Another layer of gravel or chippings, approximately five centimeters thick, is placed on top of the pipe and finally the earth on top.
Tip
If you want to lay paths in the rock garden, they also need a substructure. This prevents the path plates from sinking and ensures that they stay in place.
