Recycling GRODAN

Crop Rotation — Our most popular recycling method

Recycle GRODAN


Recycle GRODAN

Local Farms benefit from crop rotation, and so can your home garden.


  1. Grow a vegetable plant.
  2. Chop up the used slab/block into little 1/4” Grow-Cubes and remove loose root mass.
  3. Grow flowers in the chopped cubes.
  4. When you are tired of the flower, remove the plant and the loose root mass.
  5. Pot up a foliage– or house plant in the used cubes.
  6. When you are tired of the house plant, remove the plant and the loose root mass.
  7. Grow a new plant.

Other recycling ideas

Turn your stone wool into Gro-Wool™ by running it through a wood chipper. Attach a plastic ‘tent’ to catch the wool.

Use the chipped wool (Gro-Wool);

  1. To speed up your composting; add some each time you throw stuff out for composting. The stone wool aerates the compost and thus speeds up the process by 20-30%
  2. To improve the tilth of your garden soil. Add 30% wool to the first 1.5 ft. of soil.
  3. Mixing Gro-Wool into sandy soil and clay soils is especially beneficial. You will see a some quicker growth next time you plant something.
  4. as potting ‘soil’ for your potted plants.
  5. Flood barriers. Remove plastic & plants from the slabs and use them as flood barriers instead of sand bags. Do not stack more than 4 slabs on top of each other, as any beyond that will dry out (and fly off ??!) . You can stack in a double staircase shape and seed grass on the slabs, so they look nice outside of the flood season.
  6. Stack the slabs to make a raised garden bed.

Eventually mix used wool into your compost. Stone wool aerates the compost and speeds up the process.

How do the commercial growers recycle GRODAN?

Recycling in EuropeIn Europe the GRODAN is returned to our factories, where we melt it and spin new GRODAN from the used wool.

Recycling in North AmericaIn North America:
In greenhouse concentrations, such as Ontario, Canada there are companies who receive and recycle the wool, plastic and the plant material into various new products.

Recycling optionsWhere transport costs prohibit return to the factory or to a recycling plant there are a couple of options for the grower:

Once the commercial grower has finished his crop he will either steam sterilize the stone wool or take it to the landfill.

Steaming the woolSteaming the wool kills any pathogen there might be and enables him to reuse the stone wool for his next crop. This re-use process is, however, very labor intensive for the grower and often not very cost effective.

One choice is to take the stone wool to the landfill. They can use the stone wool as ‘top soil’. This means the landfill stack the slabs, so they may quickly cover a section of the landfill that is full. If They had to use soil, it would take them many loads, as soil cannot be ‘stacked on top’ of the garbage.

Some growers will make an arrangement with a local farmer, who will plow the used GRODAN into his soil, It improves the tilth of the soil and the soil also get benefit from a bit of left over fertilizer.