- Mulch is not just mulch
- Quality pays off
- Not suitable for all plants
- Apply bark mulch correctly
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Hardly any hobby gardener can do without bark mulch. It not only serves optical purposes, but also protects soil and plants. One has copied this from nature. But not every mulch is equally suitable for every soil or every plant. In addition, there are sometimes very large differences in the quality of the mulch itself. There are also a few things to consider when choosing the right product and its application.
Mulch is not just mulch
Bark mulch is chopped tree bark, a waste product from forestry. As a rule, mulch contains the tree bark of native conifers such as pine, spruce or Douglas fir. It is commercially available in different qualities and grain sizes, sometimes even in different colors, naturally dyed. Only pine bark from the Mediterranean region has an intense rust-red color by nature, which is also commercially available and can be found in more and more gardens. Pine bark mulch is said to be the best you can buy in this country.
Quality pays off
There are very big differences in the quality, especially the composition of bark mulch. There are neither regulations nor a standard as to how it must be designed. In theory, it doesn't even have to be made of tree bark. In the worst case, there is even the possibility that what is offered as bark mulch is 100% foreign matter. Partially too high a cadmium load is criticized. Cadmium is a heavy metal classified as very toxic. It is also important to mention that not every product is contaminated in this way. But how can you recognize high-quality mulch?
- An important quality feature of mulch is the smell
- Fresh mulch smells pleasantly of forest and essential oils
- The older the material, the earthier the smell
- composition is another indication of quality
- Many products often contain cheap mulch
- Cheap products often contaminated with unscreened foreign matter
- Mulch with a low percentage of tree bark contains fewer tannins
- Weeds are therefore not suppressed as effectively
- In inferior products, mulch is very fine or even powdery
- Fine material rots very quickly
- May impede oxygen exchange in soil
- High-quality mulch contains larger pieces of peeled tree bark
- A structure or bark size of 16 to 40 mm is important
- Good quality mulch keeps its shape longer
- The positive effect lasts longer
- This is the most important indication of good quality RAL quality mark 250/1-1
- Products with this seal of quality are not chemically treated
Considered as a Mercedes among the types of mulch pine mulch. It should be of the best quality. Pine bark has a high resin content, which has the property of making the mulch last for a very long time. But there are also limitations here, because even if the product says 'pure pine', that is no guarantee that it actually contains pine. Often there is also normal mulch made of conifer bark in it.
Not suitable for all plants
Mulch is undoubtedly good and recommended for many things in the garden. However, some plants have one intolerance compared to bark mulch. For all acid and humus loving plants like. e.g. rhododendrons, hydrangeas or ferns, mulching is a must as well as for shady perennials, roses and freshly planted trees, shrubs and hedges as well as on larger open spaces. You particularly benefit from this.
The situation is different with perennials and flowers in the garden, which do not tolerate permanent moisture or are dependent on a rather alkaline pH value. Vegetable beds, raspberries and strawberries should also not be mulched at all. They are more grateful for a layer of straw or grass clippings.
Apply bark mulch correctly
There is also often confusion about how to properly apply mulch in the garden. It's all about the right one time and the thickness. The best time to apply mulch is in the fall, but it is possible all year round. The coarser the material, the thicker the layer can be. Five to seven centimeters are usually recommended. Before spreading, the soil should be loosened up well, freed from any weeds and fertilized, especially with nitrogen, because the mulch removes this from the soil. But chopped tree bark has not only disadvantages, but also a lot of advantages.
The benefits of mulch are very diverse and well known, both for the soil and the plants growing on it. It is applied as the top layer on the ground, where it can fulfill its purpose and unfold its effect.
- Mulch promotes the colonization of microorganisms
- This improves soil structure and soil fertility
- With sufficient thickness, protection against natural soil erosion
- Washing away of the topsoil can be prevented in this way
- High-quality mulch regulates soil temperature and moisture in the soil
- Even in summer with persistent heat and drought
- Bark material provides protection against dehydration and frost in winter
- Prevents or suppresses excessive weed growth
- The tannic acid it contains is responsible for this
- Leads to a significant reduction in workload
- Mulch offers shelter and habitat for many small animals and insects
- Costs for conventional bark mulch manageable
- Chopped tree bark also has a decorative effect
- Mulched surfaces convey a clean and well-groomed impression
A special case is the pine bark, which is increasingly outpacing conventional mulch in popularity. The reason for this is the good quality and other advantages. For example, pine mulch has a lower acid content and therefore has a significantly less impact on the pH value of the soil than conventional mulch. It lasts more than twice as long as the bark of domestic conifers and the cadmium load is also much lower. Pine bark can also largely suppress weeds. It rots more slowly than pine or spruce and is also available in different grain sizes. Their typical red-brown coloring also ensures a well-groomed look. The good quality of pine bark is also confirmed by the RAL quality seal.
In addition to the many good properties, both mulch made from native conifers and pine mulch have one or the other disadvantage that should not be ignored.
- There is intolerance in some plants
- Coniferous mulch removes nitrogen from the soil
- Nitrogen is removed during the decomposition process
- This temporarily leads to a lack of nitrogen
- Especially problematic for flat roots
- To prevent this, fertilize the soil with nitrogen before mulching
- Bark mulch not only attracts useful animals, but also snails
- Snails use mulch for shelter and to lay their eggs
- Especially when the bark mulch is wet
- To avoid attracting them, only use pre-dried mulch
- Only mulch in dry weather
- Moisture does not accumulate so quickly under the bark material
Even though pine bark is generally said to be very good, it also has disadvantages. One of them is the lower salary tannic acid, which means that weed inhibition is not optimal. Accordingly, the soil must be prepared all the more carefully and freed from weeds before mulching. Another disadvantage is the long transport routes, because pines are not native trees. Ultimately, it is also a matter of price which type of mulch you choose, with pine mulch costing slightly more than pine, spruce and Douglas fir bark mulch.