Mulching your wildlife garden: Effective soil management in June

Key points at a glance

• Mulching protects the soil from direct sunlight and significantly reduces the rate of evaporation.
• Organic materials promote soil life, which in turn improves soil structure and water-retention capacity.
• Choosing the right material is crucial for managing nutrient input effectively.

Securing soil moisture through targeted mulching

When temperatures rise in June and rainfall becomes less frequent, many garden soils come under heat stress. In a wildlife garden, mulching is not just about covering the ground; it is about active resource management. An organic mulch layer acts as an insulator: it keeps the soil surface cool and, by breaking capillary action, prevents water from rising from deeper layers and evaporating unused.

The choice of material determines the ecological impact. While bark mulch suppresses weeds, it draws nitrogen from the soil during the decomposition process and can stress specialised plants due to its low pH level (a measure of acidity). Instead, opt for materials that close the nutrient cycle in your garden.

Comparison of common mulch materials

4 practical tips for the wildlife garden

1. Prepare the soil: Never mulch on dry, hard soil. Wait for a light rain or water the area beforehand. This is the only way to retain moisture under the mulch layer.
2. Mind the thickness: Apply organic material to a maximum depth of three to five centimetres. A layer that is too thick can lead to rot during heavy rainfall, as it hinders the soil's gas exchange (the respiration of soil organisms).
3. Using grass clippings: Only use wilted or dried grass clippings. Fresh clippings tend to rot and form an airtight mat. This is particularly beneficial for the violet ground beetle (Carabus coriaceus), which finds protection under the layer.
4. Combining with ground cover: Use living mulch layers. Plants such as bugle (Ajuga reptans) or wild strawberry (Fragaria vesca) shade the soil more efficiently than any dead material and also provide food for wild bee species like the grey-backed mining bee (Colletes cunicularius).

By mulching systematically, you create a stable microclimate. Intact soil life, consisting of earthworms (Lumbricidae) and microorganisms, ensures in the long term that the soil remains porous and can effectively absorb water when it does rain. Make sure not to use peat products, as the destruction of peatlands has a massive negative impact on the global climate.

Frequently asked questions

Is bark mulch suitable for a wildlife garden?

Bark mulch draws nitrogen from the soil as it decays and increases acidity. It is better to use perennial prunings or wilted grass clippings.

How thick should a mulch layer be in summer?

Apply organic material to a depth of about three to five centimetres. A layer that is too thick obstructs the essential gas exchange of the soil.

Can I use fresh grass clippings as mulch?

No. Fresh grass clippings clump together and begin to rot. Dry them out slightly beforehand to obtain a permeable and structurally stable layer.

Main article: Heat stress in the wildlife garden: Why dry spells promote adaptation