Tree Substrates for Healthy Root Growth

Tree Substrates for Healthy Root Growth

Product overview

Our interground-Baum substrate mixtures meet the requirements of plant pit construction methods 1 and 2 of the German FLL (Forschungsgesellschaft Landschaftsentwicklung, Landschaftsbau e.V.) and offer optimal conditions:

  • interground-Baum 0-16, tree substrate 0-16, according to FLL 1,
  • Backfilling of tree pits for new plantings and site restoration
  • interground-Baum 0-32, tree substrate 0-32, according to FLL 1 + 2,
  • Backfilling of tree pits for new plantings and site restoration
  • interground-Baum 0-32 SW, tree substrate 0-32 SW, according to FLL 2,
  • Backfilling under roads/traffic areas

The FLL "Green Roof Guidelines - Guidelines for the Planning, Construction, and Maintenance of Green Roofs" were developed from the "Principles for Green Roofing" published in 1982 and have been revised several times since 1990. They are recognized as a benchmark set of guidelines for green roofs in Germany.

Tree Substrate
Tree Substrate 0-16
Tree Substrate
Tree Substrate 0-32

Tree Substrate
Tree Substrate 0-32 SW

Plant pit construction methods

Even at school, every child learns that trees provide good healthy air. Because of the current discussions about the formation of fine dust and the climatic conditions in cities, this is more topical than ever. Trees have many positive characteristics and play an essential role in residential areas and landscaping:


Trees make a significant contribution to a positive landscape image and contribute to spatial design, especially in urban areas. Trees form a balancing pole in urban development and serve as optical shielding and upgrading and, also, to protect the road against slipping or wash-out.

Trees reduce air pollutants, fine dust, reduce CO2 by storing it in wood, and release oxygen.


Trees regulate the climate by providing a balancing temperature in the summer months, providing shade, reducing solar radiation, lowering wind speed, and reducing noise.

Trees also make a positive contribution to a balanced water balance, as the infiltration of rainwater is improved.

Therefore, we must plant trees in our surroundings to benefit from the positive effects in the future.

Tree Substrates
Tree Substrates

When planting trees, it must be noted that they are often not adequately planted and maintained only to fulfil their task. Trees are also complex creatures. They can only achieve their functions if they are healthy and vital.


Therefore, there are some things to consider, especially in urban environments. 

  • The planting pits of trees often have little root space available. Usually, a tree needs a root system that is larger than the crown of the tree.
  • Due to the increasing number of sealed areas and increasing pollutants, trees' growing conditions have deteriorated considerably, especially in cities. 
  • Plant pits often allow only a little water. 
  • The soils are often compacted by construction work. It causes a lack of oxygen, which hinders root growth and promotes waterlogging.
  • Tree plantations in unsuitable soils lead to weak growth, as water and nutrients cannot reach the roots sufficiently. 
  • In most cases, the ground offers few nutrients and is also polluted by urine and salt.

As a result, the trees often lose their stability and walkways and roads.

Tree Substrates
Tree Substrate

iNTERBiMS GmbH produces mineral / organic tree substrates for trees. Thanks to the open-pored structure, high treading and storage stability, high frost resistance, and the balanced ratio between water permeability and storage capacity, individual substrate requirements are fulfilled "par excellence" even in deep layers.

INTERBIMS offers individual mixtures as well as delivery to the construction site.


Tree substrates contribute to the sustained growth and growth of trees and promote their air and water balance. Our tree substrates consist of mineral substrates with small amounts of organic matter.


interground-Baum substrates are available in several variants, following the construction methods in the FLL (Forschungsgesellschaft Landschaftsentwicklung, Landschaftsbau e.V.) recommendations for plant pit construction methods and substrates.

The Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e.V. (Research Society for Landscape Development, Landscaping) has drawn up recommendations for tree planting in 2 parts, which are generally accepted.


In the "Recommendations for Tree Plantings - Part 1: Planning, Planting, Maintenance", sustainable guidelines are defined for tree plantings, from planning to achieving the intended functions.

In the "Recommendations for Tree Plantations - Part 2: Site Preparations for Tree Plantations; Planting Pits and Root Zone Expansion, Construction Methods and Substrates", minimum requirements are defined for this purpose, especially for tree plantations on traffic areas and in populated areas, if the existing soil is not suitable for the intended plants and uses.


The recommendations of the FLL, therefore, distinguish between the following two areas of application:

Tree substrates for open, uncovered planting pits (planting pit construction 1),  whose surface is only slightly stressed.

Tree substrates for covered plant pits (plant pit construction 2), whereby the plant pit backfilling is the plant location and the building ground for the traffic areas. 

Product Characteristics

The requirements for a permanently stable soil skeleton are high since the substrate must serve the tree for a long time. interground-Baum substrates forever ensure the necessary air and water balance. With proper structural stability, a larger pore volume is provided even in deep layers.

These are characterized as follows:

  • on a natural volcanic basis such as pumice and lava
  • good water storage capacity
  • structurally stable
  • load-bearing
  • resistant to dislocation
  • improved nutrient supply
  • optimized root development
  • is more germ-free than soil
  • can be processed in all weathers
  • optimal quality

iNTERBiMS offers individual tree substrates and their delivery to the construction site in all common delivery forms:

Tree Substrate 0-16 

Tree Substrate 0-32

Delivery forms

Other forms of delivery are on request.

All products are subject to quality control (external and internal monitoring) following the German FLL guidelines.

 ✓   Truck 

 ✓   Big Bag at 1.00 m³ / 1.50 m³

Available with humic substances or low pH value on request.

Please feel free to contact us at any time. We will be happy to advise you!



Project examples

Project examples
Project examples