Bio Dünger

Top 5 mineral substrates for indoor plants

Top 5 Mineralische Substrate für Zimmerpflanzen - FARBIO® - Nachhaltige Bio-Flüssigdünger aus Hamburg

Plants need a substrate to grow, this can be organic soil or a mineral substrate. Some plants are easier to cultivate in such substrates because they are native to areas that do not have a high humus content in the soil. Non-living material prevents uncontrollable processes in the soil and indoor plants can be better cared for. We will introduce you to different components and their properties so that you can mix an ideal indoor plant substrate!

Difference mineral and organic

Organic components are alive and create an optimal environment for effective microorganisms. One increasingly speaks of earth or soil and not of substrates.

mineral Components are of non-living origin and serve as growth substrates for plants. They contain little to no nutrients.

Good mineral Substrates for most indoor plants

The different elements can be used individually as a growing medium or mixed together to provide your plant with the ideal soil mix. Organic material can also be added at will.

expanded clay

The starting material is clay, which contains organic components. However, these burn at high temperatures and inflate the clay to almost five times its size. The result is clay balls with many pores inside. It does not mold and is permanently structurally stable. This makes it ideal for use in pots, where it is mainly used for drainage. However, expanded clay is not able to store large amounts of water. The pH is between 6.2 and 7.5.

expanded clay


The white volcanic rock is heated and as a result it develops a structure like popcorn. This mineral is dusty, can break down under pressure, and will degrade on its own after about 5 years. It has many advantages: It gives potting soil a loose texture and allows plant roots to grow healthily through sufficient oxygen. It is also sterile and pH neutral. Perlite is rather cheap and available in different grain sizes.


This mineral is a light and porous aluminum silicate ejected during volcanic eruptions. German pumice is sterile and pH neutral, but from other countries it can have a pH as high as 8.5. Pumice stone can be used to loosen your soil. This gives the roots access to air and water, which helps absorb nutrients and improve plant health and development. Similar to expanded clay, however, it is also suitable for hydroponics.



Cooled lava can be crushed and then used as an inorganic material for soil substrates or as a permanent layer of mulch. Lava rock very porous, breathable and water permeable. It can ensure constant moisture and temperature in the soil. The pH value depends on the lava type, usually it is between 6.0 and 7.0.


Zeolite is a group of aluminosilicates - they are of volcanic origin. The so-called clinoptilolite is suitable for indoor plants and in the garden. The use of zeolite can lead to fertilizer and water savings and optimize the nutrient potential in the soil. A proportion of 40% zeolite in the soil substrate is ideal for popular tropical indoor plants such as philodendron or anthurium. Zeolite is available in a variety of grain sizes - from zeolite flour to sand. Zeolite grains up to 8mm can be used for palm trees and cacti. It should be noted that when using zeolite, the pH can increase over time.

What is hydroponics?

With hydroponics, the plants are not grown in potting soil but in water. Soil isn't essential for plants to grow, as its main purpose is to provide a base for the roots to cling to. However, it can also mineral Substrates such as expanded clay are used. This culture method is suitable for most plant species.

For this you need a planter and an inner pot, fill in your minerals and pot your houseplant. It is important to wash out the roots beforehand and finally put a water level indicator in the pot. There must always be a certain amount of water in the plant pot so that the plant can survive.

Since non-organic substrates, unlike potting soil, do not provide any nutrients, you must fertilize with important nutrients such as nitrogen, phosphorus and potassium with every watering. All FARBIO® fertilizers can be used for hydroponics and will not burn the roots! The FARBIO® NPK organic liquid fertilizer for green plants is very well suited to providing your plants with the essential main nutrients.

Advantages: Without peat and compost

If you use a growing medium free of organic elements such as humus, white peat or wood fibers, this reduces the likelihood of disease and pest infestations in your plant, for example root rot due to waterlogging. mineral Substrate can be easily sterilized and thus reused. It will improve soil drainage and aeration when mixed into regular soil mix. In addition, there are different particle sizes of the minerals.