• RETENTIS® im 20kg Sack aus Kraftpapier
  • Timelapse-Video über 21 Tage: Zwei identische Basilikumtöpfe, links in Erde mit 2 % RETENTIS®-Wasserspeichergel von Agrobiogel, rechts in herkömmlicher Erde. Ohne Bewässerung bleibt die RETENTIS®-Pflanze sattgrün und vital, während die unbehandelte Pflanze sichtbar vertrocknet.
  • Agrobiogel dark granular hydrogel soil water retention product spread on white surface
  • Plant roots suspended in soil demonstrating hydrogel soil water retention by Agrobiogel
  • Agrobiogel RETENTIS container plant demonstrating hydrogel soil water retention at roots
  • Illustration zur Anwendung von RETENTIS®-Wasserspeichergel: 1. Gel mit Erde oder Substrat mischen, 2. Pflanzen einsetzen, 3. Gießen. Illustration: RETENTIS® im Pflanzgefäß anwenden
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Biological water reservoir made from wood

RETENTIS® 20 kg

RETENTIS® 20 kg

€139,90 EUR
€139,90 EUR
€7,00 kg
Sale Sold out
Taxes included.
  • Stores up to 10 l of water per kg
  • Active in the soil for 3–5 years
  • Delivery in 2 to 5 working days within Austria
Your legal guarantee rights (at least 2 years)

Legal guarantee of conformity

Every product in this shop comes with a legal guarantee of conformity of at least two years. The official EU notice sums up your rights.

Harmonised EU notice on the legal guarantee of conformity: at least two years of legal guarantee for goods sold in the European Union

europa.eu/youreurope/guarantees ↗Open page with all details →

Free shipping (included in price) within Austria. Delivery time: 2 to 5 working days within Austria.

For more than 2 sacks, pallets or big bags, we are happy to send you an offer.

Delivery to Germany or another EU country? Send an enquiry

Our online shop currently delivers within Austria only. Tell us where the 20 kg sack should go and we will send you an offer including shipping.

We use your details only to answer your enquiry. More in our privacy policy.

Or write to us directly: office@agrobiogel.com

RETENTIS® turns your soil into a water reservoir.
Work the granules in, plant, water in thoroughly. Made from lignin, a natural component of wood, RETENTIS® stores up to 10 liters of water per kilogram and releases it to the roots over a long period.

RETENTIS® stays active in the soil for 3–5 years, has a near-neutral pH (6.4–7) and can be combined with fertilizer. No synthetic polymers, made from a by-product of the timber industry, made in Austria.

The sack contains 20 kg and covers up to 1 m³ of soil (at 20 g/l), about 100 m² of perennial bed (at 200 g/m²) or about 200 m² of lawn (at 100 g/m²).

It's that easy

1. Mix: mix in 10–20 g per liter of soil evenly. Never put it into the planting hole on its own.

2. Plant: plant as usual. Tip: add 2–3 cm of untreated soil on top.

3. Water: water in thoroughly so the granules absorb water and turn into a gel.

Fertilizer can be mixed in at the same time. RETENTIS® does not replace fertilizer.

Dosage

Containers, balconies & raised beds: 10–20 g per liter of soil, mix in evenly

Perennials & ground cover: 200 g/m², mix into the top 20 cm

New lawn or overseeding: 100 g/m², work in dry, about 10 cm deep

Existing lawn: 20–40 g/m², apply with quartz sand during aeration

Shrubs & trees: 10 kg per m³ of excavated soil, mix thoroughly

Root dip gel: 0.5–0.7 kg per 10 l of water, let swell for 10–15 minutes while stirring several times, dip the roots for a few seconds

What one sack covers (20 kg)

  • 1 to 2 m³ of soil for raised beds, planting pits and large containers (at 10 to 20 g/l)
  • about 100 m² of bed with perennials or ground cover (at 200 g/m²)
  • about 200 m² of lawn for new lawns or overseeding (at 100 g/m²)
  • about 2 m³ of excavated soil for shrubs and trees (at 10 kg/m³)

Why RETENTIS®

  • Stores up to 10 l of water per kg and releases it to the plant over a long period
  • Active for 3–5 years in the soil
  • No synthetic polymers, no microplastics in the soil
  • Near-neutral pH (6.4–7), combinable with fertilizer
  • Listed for organic use on the FiBL input list (EU) and the EasyCert list (AT)
  • Made in Austria, produced from lignin, a by-product of the timber industry

Good to know

In containers, the draining water may be slightly brownish at first. Best to use a saucer.

Unopened and stored cool and dry, shelf life of more than 24 months.

Close opened sacks tightly and store them dry.

View full details

Tried and tested

What happens in your soil

Storage capacity, up to

10 l

of water per kilogram of granules, released to the plant over a long period.

Source: Product data sheet (German), p. 2

Peat-free soil, after 10 days

55 %

moisture loss with RETENTIS®. Without additive: up to 88%.

Source: White Paper 2026 (German), p. 9

Active period

3–5

years active in the soil. Mixed in once, effective for several gardening seasons.

Source: Product data sheet (German), p. 2
Two basil plants on day 0, both equally healthy
The same basil plants after 21 days without water: left with RETENTIS® still healthy, right dried out
2 % RETENTIS® soil only

Basil under drought stress

21 days. Not a drop of water.

Two basil plants, one difference: on the left 2 % RETENTIS® in the soil, on the right without. No water for three weeks.

Drag the slider and see for yourself.

AgroBiogel pot trial under identical conditions.

RETENTIS® 750g - Agrobiogel. RETENTIS® 750 g Standbodenbeutel im Garten, Vorderseite

Smaller area? The 750 g pack.

For balconies, containers and small beds, RETENTIS® comes in the 750 g pack, with free shipping within Austria. That covers 37.5 to 75 liters of soil.

To the 750 g pack →

How much do you need?

Enter the area, number of plants or pot: RETENTIS®Calc calculates the amount and the right pack size.

Calculate requirementAll applications