The weight of wet earth is usually relevant when it comes to moving large amounts of it. How much water the earth can absorb depends on its composition.

In a nutshell

  • Wet soil has a higher dead weight than dry soil
  • The earth's own weight depends on the material and the general soil density
  • When calculating the statics, the weight of wet substrates can be relevant

Composition of the substrate

There are certain substrates that have very good properties in terms of absorbing water, while others hardly have any and water only sticks to their surface at most. Therefore, in order to be able to calculate how much wet soil weighs, it is first and foremost important to know the composition of the soil.
Common soil types are:

  • clay soil
  • sandy bottom
  • humus soil
  • peat soil

The garden is dominated by a mixture of clay and sandy soil, which still has a small amount of organic humus. If you want to know the exact storage capacity of your soil, you would have to have a soil sample analyzed in which all components are listed.
These analyzes are usually very expensive, which is why the proportions are often only estimated. You can also do this yourself by taking several samples from your garden. They moisten them and try to form a sausage out of them. If a strand is easy to knead, the proportion of clay is higher. However, if the strand crumbles easily or cannot be shaped properly at all, the proportion of sand is higher.

density

Density is relevant in two areas. On the one hand, the density of the individual components of the soil must be used. A cubic meter of rock is heavier than a cubic meter of roughly organic humus. The reason for this is that the rock itself has a higher density than the humus.
However, the density itself also plays a role in the composition of the soil. A dense soil made of finer material usually has a higher weight than a soil made of coarse material.

Measure residual moisture

Basically, no soil is 100% dry, because the humidity alone ensures that there is always a certain amount of water. There are different methods of determining the moisture in the soil. There are also special measuring devices with which the moisture can be determined.
In soil science, soil is basically divided into five categories with regard to soil moisture:

  • wet
  • wet
  • fresh
  • scrawny
  • dry

With an average amount of rainfall and an average garden soil, it is mostly a fresh soil. This means that if the earth is touched, it feels fresh and at most slightly damp. If the soil is compressed, no water should run off the fresh substrate, otherwise one would speak of your moist soil.

Notice: The soil moisture is usually only a snapshot and can already have a different residual moisture in a few hours, for example after a downpour.

note statics

Wet soil is usually not a lightweight. In the garden, moisture plays a subordinate role in relation to its own weight. The situation is completely different when the substrate has to be transported or in the case of roof gardens. It is often underestimated how heavy wet earth can be, which can subsequently lead to subsidence of ceilings and serious damage to the building fabric.

Tip: There are special substrates for roof gardens that are even suitable for growing vegetables. They have a low weight and can store water very well.

Moisture must also be taken into account when transporting earth material, as the maximum permissible total weight must not be exceeded. So if you want to have substrate transported, you should pay attention to the density of the substrate and a low residual moisture content, as this means that a larger quantity can be transported.

weight calculation

Conventional garden soil has an average density of 830kg/m³. This corresponds to a weight of 0.83 kg per liter if the soil were completely free of moisture. Water itself has a density of around 998kg/m³, which corresponds to a weight of rounded up to one kilogram per liter. For the conversion, the weight of the substrate and the proportion of water are added.

Calculation example for 1 liter (0.001m3) potting soil and 1 liter (0.001m3)Water:

Weight wet soil: 0.83kg (dry soil) + 1kg (water) = 1.83kg

The amounts of water refer to average rainfall. 20 liters of water per square meter in six hours is considered heavy rain. Amounts of up to 0.01 cubic meters, which corresponds to 10 liters of water, are common in an average downpour.

frequently asked Questions

How much water does a garden soil contain on average?

On average, the soil has a water content of 20 to 40 percent.

How to reduce moisture from wet soil?

A simple method is to cover and create drainage ditches.

Does the weight of frozen substrate change?

Yes, the portion of water in the soil that becomes ice has a lower weight compared to liquid form. Frozen substrates are therefore slightly lighter.

Category:

Garden maintenance