Unsealing soil allows it to do what it does best again: Store water, nutrients and carbon, provide a habitat and cool the environment. This creates a healthier urban climate and more space for plants and animals. Unsealing soil allows it to do what it does best again: Store water, nutrients and carbon, provide habitat and cool the environment. This creates a healthier urban climate and more space for plants and animals.
You should observe the following steps:
Obtain advance information if necessary
If the site is a current or previously used industrial or commercial property - or such a suspicion exists - the Lower Soil Protection Authority should be asked whether the soil could be contaminated. If the soil is contaminated, unsealing can be problematic because pollutants could enter the groundwater.
Removal of sealed layers such as asphalt, concrete or paving stones etc.
Paving stones can be removed with a spade edge, a chisel or a pickaxe, for example. Asphalt or concrete surfaces can be broken up and removed with a chisel/drill/demolition hammer.
Gardening equipment and tools can be hired from a rental equipment service or construction machinery and equipment service or from DIY stores. Cost example: A pneumatic hammer with a compressor costs approx. 100 euros/day, an electric chisel hammer approx. 50 euros/day.
Loosen and, if necessary, remove the compacted soil to restore the infiltration capacity and rootability
The subsoil is often heavily compacted as it has carried a heavy load over many years. The subsoil, or base layers, should be loosened as deeply as possible, as many plants benefit from a permeable structure that allows rainwater to seep away. For shallow-rooted plants, loosening to a depth of around 30 to 60 centimetres is usually sufficient.
Base layers of sand or gravel can remain in the soil after loosening. However, if materials such as building rubble, slag or other foreign substances are found under the sealing and/or the material has a chemical-oily odor, it should be removed and replaced with sand or clay.
Possible machines/tools: garden hoe, pickaxe, spade, digging fork, sow tooth or shovel.
Application of topsoil
To feed the plants, 10 to a maximum of 30 centimetres of compost is applied at the end. A mixture of topsoil and mature compost (approx. 3:1) is particularly suitable. It promotes soil life, improves the structure and provides nutrients - ideal conditions for new greenery. After application, press down lightly so that it does not sink, but remains loose enough to allow water and air to penetrate.
Planting/greening
For a high level of biodiversity, it is advisable to plant beds with native wild plants. They provide a reliable source of food and therefore an important basis of life for the native insect world. In turn, a species-rich insect population also supports birds that feed on them. The greater the diversity of insects, the more attractive a site becomes for numerous bird species. In addition, native wild plants are considered to be particularly robust and drought-tolerant. Suitable species are, for example, broom broom, dyer's broom, round-leaved bellflower, ball bellflower, catmint, cicely, red campion, snow marbel, immense leaf or nettle king. After selecting the plants, the root ball should be carefully loosened, the plant inserted deep enough and then pressed down firmly. Alternatively, a suitable seed mixture can be sown according to the instructions on the packaging.
Newly planted plants should be watered thoroughly. If planted deep enough, the water will reach the roots directly as if through a funnel - an ideal start for healthy growth. In the following days, top up with water if necessary. Additional seeds of native wild plants can be sown around the plants to further green the area and promote biodiversity. Some species require more intensive care; corresponding tips and recommendations can be found in specialist literature or via horticultural information sources.
The costs for surface unsealing depend on
- the size of the area to be unsealed
- the disposal costs of the demolition material (asphalt, paving stones, base courses, etc.)
- the costs for the redesign
- the costs for devices
This guide is based on "How to pave over in 5 steps!-Quick guide for your unsealing project" from the "abpflastern" initiative.