For landscape architects, urban planners and contractors, RETENTIS® is a practical solution for climate-resilient planting. It provides clear data, predictable dosing and straightforward specification in tenders.

Design professionals gain greater planning reliability. RETENTIS® can be clearly integrated into technical specifications, documented transparently and helps reduce the risk of plant losses during dry periods—without adding technical complexity.

Clients and operators benefit from reduced irrigation and maintenance requirements during the establishment phase, as well as fewer replacement plantings.

Contractors receive a solution that is easy to calculate and compatible with established installation processes. This results in less follow-up maintenance, fewer warranty cases and fewer irrigation trips.

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Technical Specifications

Organic water and nutrient retention granulate based on lignin (without synthetic polymers).

Absorbs water and forms a reservoir that stores moisture and releases it gradually in the root zone. In addition, it retains dissolved nutrients (reducing leaching while ensuring plant-available supply) and gradually decomposes into humus-like structures over time.

  • Form: Black-brown granules
  • Base component: Lignin (without synthetic polymers)
  • Particle size: 0.5–4.0 mm (≥ 90% within range)
  • Density: approx. 700 kg/m³
  • Bulk density: 600–750 g/l
  • Water storage capacity: up to 10 g water/g (≈ 10 l/kg)
  • Activity period: 3–5 years (in soil)
  • pH value: 6.4–7.0
  • Solubility: forms a gel when combined with water
  • Storage class: LGK 13 according to TRGS 510

Approvals / Certifications (excerpt)

  • Austria: Product approval according to § 9 DMG 2021 (valid until 2033)
  • EU: Marketed under Regulation (EU) 2019/515 (mutual recognition) in accordance with the declaration of conformity
  • Listed in: FiBL Input List (EU) and EasyCert Input List (Austria) for organic farming
Download Technical Data Sheet

Application Guidelines (specification-relevant)

  • Mix dry and uniformly with soil / earth / substrate.
  • Do not apply superficially; typically incorporate at a depth of 10–30 cm (project-specific).
  • Water thoroughly after installation to initiate swelling.
  • Standard fertilisation can be maintained; mixing with fertiliser is permitted.
  • For planting containers: slightly brownish drainage water may occur initially; provide saucers if required.

Practical note for designers and site supervision:
The mixing zone, quantity, installation depth and homogeneity, as well as delivery notes and batch numbers, should be clearly documented in the execution documentation.

Note for Tender Specifications

Tender Specification Text

Supply and install/incorporate an organic water retention granulate based on lignin/wood (without synthetic polymers) to improve water and nutrient retention in the root zone. Water storage capacity: up to 10 g water per g of product. Effective activity period: 3–5 years. Installation by homogeneous mixing with soil/substrate. Apply dry and incorporate into the soil; do not apply superficially.

Supplier Reference

AgroBiogel GmbH
Königstetter Straße 128–134
3430 Tulln
AustriaMobile: +43 664 4202 158
E-mail: office@agrobiogel.com

Equivalency Criteria

Only materials/measures intended to increase water availability in the soil that are bio-based, microplastic-free, and free from synthetic polyacrylate superabsorbent polymers (SAP) shall be considered equivalent.

Applications in Landscaping and Recommended Dosage

Guideline values; project-specific determination depending on soil/substrate, root zone, irrigation regime and climatic conditions.

  • Soil / substrate mixtures (including roof substrates):
    10–20 g per litre of soil or substrate; mix evenly and dry with soil or substrate.
  • Lawn seeding / turf establishment:
    100 g/m²; incorporate to a depth of approx. 10 cm.
  • Plantings (ground covers, perennials):
    200 g/m²; incorporate to a depth of approx. 20 cm.
  • Planting pits:
    10 kg/m³; mix thoroughly with excavated soil.

RETENTIS® Planning Tools & Calculators

Our calculators help planners quickly and transparently determine the required quantities of RETENTIS®, the treated substrate volume and the associated costs. Depending on the application, a landscaping calculator for perennial, shrub and area plantings as well as a tree planting calculator for applications in the root ball zone are available. Simply open the appropriate calculator, enter the relevant parameters and use the results directly for planning, scenario comparison and cost estimation.

RETENTIS® Landscaping Calculator for Perennials & Shrubs

This calculator helps landscape architects and planners determine the required quantities of RETENTIS® for perennial, shrub and area plantings.

Click “Open Landscaping Calculator” to start planning.

RETENTIS® landscaping calculator for perennials and shrubs
AgroBiogel GmbH – Landscaping

How to Use the RETENTIS® Landscaping Calculator for Perennials & Shrubs

Calculation Mode

In “Number of Plants” mode, the calculation uses 0.1 kg of RETENTIS® per plant, for example for specimen shrubs, woody plants or individual plantings. In “Area” mode, the calculation uses 0.2 kg of RETENTIS® per square metre, for example for perennial planting areas or mixed plantings of normal density. The modes “kg/Litre Substrate – 10 g/L” and “kg/Litre Substrate – 20 g/L” are intended for very high planting densities of approximately 15–20 plants per square metre, particularly in very sandy, highly permeable substrates. In these modes, the substrate volume is calculated from the entered area and the mixing depth.

Input Parameters

Depending on the selected mode, enter the number of plants, the area in square metres, and the plant density (plants per square metre). In addition, specify the thickness of the mulch layer and the substrate layer in centimetres. (The thickness of the mulch layer does not affect the calculation.) The RETENTIS® mixing depth in the substrate defines the upper zone where the granulate is actually incorporated, for example the top 10 cm. A mixing depth of 10–20 cm is recommended. The price per kilogram of RETENTIS® can be adjusted to calculate the total cost and the cost per plant.

Results & Visualization

Click “Recalculate” to process the entered values. The calculator provides the total number of plants, the total quantity of RETENTIS®, the amount per plant or per square metre, the total price, and the average cost per plant. The cross-sectional diagram on the right automatically adjusts to the entered layer thicknesses and the selected mixing depth, illustrating the position of the RETENTIS® granulate within the substrate.

Dosage Guidelines

If the number of plants per square metre is below three, a note appears indicating that the calculation should preferably be carried out per plant. The kg/litre variants intentionally result in higher application rates and are intended only for very dense plantings and sandy substrates. Their use should always be technically justified and assessed on a project-specific basis.

Documentation and Reset

The “Download results (CSV)” button allows the calculation to be documented and the data to be used in quotations or project documents. The “Reset calculator” button restores all inputs to the default values so a new calculation can be started quickly and cleanly.

RETENTIS® Tree Planting Calculator

The calculator helps planners determine the RETENTIS® requirements for tree plantings, including quantities, treated substrate volume, and a cost overview. Simply click “Open Tree Planting Calculator” to start planning.

Using the RETENTIS® Tree Planting Calculator

Calculation Basis

First, the project-specific basic data for the tree planting are entered. This includes the number of trees to be planted and the planting pit volume per tree in cubic metres. In addition, the share of the substrate per tree that will actually be mixed with RETENTIS® is defined (e.g. in the root ball zone). Based on this, the calculator determines the total treated volume and the resulting RETENTIS® requirement.

Input Parameters

In addition to the number of trees and the planting pit volume, the desired application rate in kg of RETENTIS® per m³ of substrate is entered. By default, 10 kg/m³ is preset (recommended dosage in the root ball zone). The price per kilogram can also be entered so that the calculator determines not only the material quantity but also the project-related costs. Project details can optionally be added in the notes field.

Results and Visualization

Click “Recalculate” to process the inputs. The calculator provides the total RETENTIS® requirement, the treated substrate volume, the total price, and the price per tree. The diagram on the right automatically adapts to the inputs and schematically shows the tree planting structure with RETENTIS® applied in the root ball zone.

Dosage Guidelines

The calculation results can be used for internal planning, cost estimation, and project documentation. Optionally entered notes help assign the results to specific construction projects or project stages. The results should be checked against the technical specifications and the specific project design before tendering and execution.

Reset and New Calculation

For a new calculation, the inputs can be adjusted and recalculated. This allows different scenarios (e.g. varying dosages or treated substrate volumes per tree) to be quickly compared and evaluated.

Delivery, Packaging & Storage

Delivery forms:

  • Paper bag 20 kg (on CP1 pallet 25–32 pcs., 500–800 kg)
  • Big bag on CP1 pallet 500–750 kg
  • CP1 pallets (1000 × 1200 × 138 mm)

Storage:

  • Store in a cool and dry place
  • Non-hygroscopic: does not clump, remains free-flowing
  • Shelf life: unopened > 24 months
Learn more about the RETENTIS® effect →

Further Application Areas

Discover additional application areas of RETENTIS® and find the perfect solution for your project.

Find more application areas →