A careful look at garden beds while walking shows that more and more exotic looking gravel is being used as a mulch layer. These are lava stones that offer many advantages as mulch.
In a nutshell
- Lava mulch is a natural product
- is also mined in Germany
- good alternative to bark mulch
- has many advantages, but also a few disadvantages
lava mulch
Lava mulch, also called lava gravel, is nothing more than solidified lava rock. It is therefore a natural product. Lava is formed when a volcano spews magma or comes to the surface in liquid form. Flowing like solidified lava is called a lava flow. This is mined and processed into lava mulch. Since lava rock is also mined in Germany, you do not need to resort to a product with long transport routes.
Coarse lava mulch
Lava gravel has a number of advantages, but there are also disadvantages, especially if the lava rock mulch is used in the wrong places in the garden.
benefits
The layer applied should be six to eight centimeters thick so that lava granulate can optimally develop its positive properties.
Gardening Benefits
structural stability
If the bed has to be entered when gardening, pressure is exerted on the ground. As a result, it becomes dense, which has a negative effect on the soil's water and air balance and damages the bedding plants. This problem can be solved with lava chippings, as it removes the pressure that occurs when you walk on it, so there is no soil compaction.
longevity
If you use lava stones instead of bark mulch, there is no need for the annoying "after-mulching".
Because lava gravel doesn't rot or degrade, you don't need to replace the mulch layer annually.
Notice: If you find out after a while that you don't like lava mulch in the bed, you don't have to remove it, you can undermine it.
walkability
Since wet bark mulch is slippery, accidents can easily occur after a rain shower when the mulched garden bed has to be walked on. This danger does not exist with lava gravel. In addition, your garden shoes stay clean because the rock does not become greasy or dirty from the soil.
weed reduction
The rapid drying of the lava mulch layer impairs the colonization of flying weeds. But the growth conditions are also poor for other unwanted plants, as their roots can hardly find a foothold on the granules.
Benefits for bedding plants
water balance
If bark mulch is exposed to high levels of moisture over a longer period of time, it becomes susceptible to mold growth, for example.
Lava gravel reduces water evaporation from the soil surface and prevents the top layer of soil from drying out. This means that the soil is better aerated. Since the surface of lava rock dries very quickly, the risk of viruses, bacteria or fungi nesting in the moist environment of the mulch is reduced.
nitrogen content
Since lava gravel does not rot, it does not use nitrogen from the soil. Therefore, additional nitrogen fertilization is not necessary.
temperature regulation
Lava rock keeps the ground cool and moist in summer. In winter, it protects the soil from cooling down, as it warms up during the day and gives off the heat to the bottom of the bed during the night.
optics
Lava mulch is available in black, gray and brown tones, which significantly increases the scope for design compared to bark mulch. Another optical element is the grain. However, you should not use too large ones, as this makes it difficult to plant new plants. Grits of are ideal
- two to eight millimeters or
- eight to twelve millimeters
Notice: You can also mix different grits to achieve a special effect.
disadvantage
Although lava granules can be used for crops and ornamental plants, they are not suitable for all areas in the garden. So you should not spread it under trees or deciduous shrubs, as the fallen leaves are difficult to remove from the mulch layer.
Lava stones have no place in the lawn!
Since this also applies to mowed grass, you should not use lava granules in the immediate vicinity of the lawn. In addition, smaller lava particles falling on the lawn can damage the lawn mower.
weed
If weeds settle between the lava particles, for example because the grain size was too large, it is very difficult to remove them. In addition, the top layer is destroyed by the unwanted plants, which means that the mulch layer has to be straightened again.
Replanting/Remodeling
If new plants are to come into the bed, it is very difficult to insert them into an existing layer of lava mulch, as the particles cannot be pushed aside so easily. Therefore, you should plan a garden bed well in advance, on which you want to spread lava particles.
costs
Lava chippings usually cost a little more than conventional bark mulch, but this is offset by the longevity of the material.
frequently asked Questions
Can I use lava stones for potted plants?Yes, the lava mulch is also suitable for pot culture without any problems.
Can lava chippings prevent waterlogging in the ground?Lava stones ensure that rainwater can drain off easily. It is said to have the same effect as a drainage in the ground.
Can I also apply lava granules in the rock garden?Yes, the lava rock is suitable for mulching rock or prairie gardens.