Lava stones: pros and cons of lava mulch & gravel

A careful look at garden beds while walking shows that exotic-looking gravel is increasingly being used as a layer of mulch. These are lava stones that offer many advantages as mulch.

Lava mulch

Lava mulch, also called lava gravel, is nothing more than solidified lava rock. So it is a natural product. Lava is created when a volcano spits magma or comes in liquid form to the surface of the earth. Flowing and solidified lava is known as a lava flow. This is broken down and processed into lava mulch. Since lava rock is also mined in Germany, you do not need to use a product with long transport routes.

Lava gravel has a number of advantages, but it is also associated with disadvantages, especially if the lava stone mulch is used in the wrong places in the garden.

advantages

So that lava granules can optimally develop their positive properties, the applied layer should have a thickness of six to eight centimeters.

Advantages in gardening

Structural stability

If the bed has to be entered when gardening, pressure is exerted on the ground. As a result, this condenses, which has a negative effect on the water and air balance of the earth and damages the bedding plants. This problem can be solved with lava gravel, as it removes the pressure that occurs during the inspection, so there is no soil compaction.

longevity

Because lava gravel doesn't rot or degrade, you don't need to renew the mulch layer annually.

Note: If you notice after a while that you do not like the lava mulch in the bed, you do not have to remove it, you can undermine it.

Walkability

Since wet bark mulch is slippery, accidents can easily occur after a rain shower if the mulched garden bed has to be entered. This risk does not exist with lava gravel. In addition, your garden shoes stay clean, as the rock does not become greasy or dirty through the soil.

Weed reduction

The rapid drying of the lava mulch layer enables the settlement of the approaching weed worsened. But the growing conditions are also poor for other undesirable plants, as their roots can hardly find a hold on the granulate.

Benefits for bedding plants

Water balance

Lava chippings reduce water evaporation on the soil surface and prevent the upper soil layer 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 other bacteria in the moist environment of the mulch is reduced mushrooms nest.

Nitrogen content

Since lava chippings do not rot, they do not consume nitrogen from the soil. For this reason, additional nitrogen fertilization is not necessary.

Temperature regulation

Lava rock keeps the soil cool and moist in summer. In winter it protects the soil from cooling down, as it warms up during the day and transfers the heat to the bed base during the night.

optics

Lava mulch is available in black, gray and brown tones, which significantly increases the creative freedom compared to bark mulch. Another optical element is the grain. However, you should not use too large a size, as this makes it difficult to plant new plants. Grains of

• two to eight millimeters or
• eight to twelve millimeters

Note: You can also mix different grains to achieve a special effect.

disadvantage

Although lava granules can be used for crops and ornamental plants, it is not suitable for all locations in the garden. So you should not apply it under trees or deciduous shrubs, which are difficult to remove the fallen leaves from the mulch layer.

Since this also applies to mown grass, you should not use lava granules in the immediate vicinity of the lawn. In addition, smaller lava particles that get on the lawn can damage the lawnmower.

weed

If weeds settle between the lava particles, for example because the grain size has been chosen too large, it is very difficult to remove. In addition, the surface layer is destroyed by the unwanted plants, which means that the mulch layer has to be straightened again.

New plantings / remodeling

If new plants are to be added to the bed, it is very difficult to insert an existing layer of lava mulch, as the particles cannot be pushed aside so easily. Therefore, you should plan well in advance a garden bed on which you want to finally spread lava particles.

costs

Lava chippings usually cost a little more than conventional bark mulch, but this is compensated for by the longevity of the material.

frequently asked Questions