Peat vs GRODAN

Is there really a difference?

There are many important differences between GRODAN and peat/soil mixes. 

  • Sustainability is the biggest difference. The majority of GRODAN products can be recycled whereas using peat actually depletes a valuable natural resource.
  • Plants grown in GRODAN absorb nutrients and water much more efficiently because it is inert, meaning that nothing inhibits the plant’s roots from accessing what it needs.
  • Since GRODAN won’t release debris into your nutrient reservoir, it can be used in recirculating systems which conserves water and expensive nutrients.
  • You will attain higher yields and better quality in plants grown in GRODAN versus peat. This Is the reason GRODAN products are the choice of most commercial greenhouse growers.
  • When you need it, we are there with unparalleled technical support that will help you succeed.
  • Plants grown in GRODAN grow faster. They don't go through transplant shock so there is never a drop in growth rate.
  • Cleanup is much faster and easier, saving you time and energy.
  • Time savings in preparation and transplanting leaves more time for social life!
  • GRODAN does not chemically bond to the fertilizer, making it much easier to flush and reducing the risks associated with salt accumulation.
  • Uniformity of evaporation allows for a more regular irrigation schedule.
  • Pest and fungal problems are far less prevalent and easier to treat effectively.
  • It takes less space to grow more! You can use less GRODAN compared to peat and grow bigger plants!

Bottom line:  GRODAN stone wool is better for the planet, better for your wallet and AWESOME for your plants!

Name/Overview for Experiment: How does the medium impact the roots?

In our experiment we used a high-tech instrument called an Irrometer tensiometer to measure the amount of vacuum the media exerts on the roots. Essentially this means that this instrument measures how much the media is resisting the plant taking up water and nutrients – less resistance, less stress on the plant and better results.

Side note: 
*= Irrometer tensiometers used in this experiment were purchased from Irrometer Co., Riverside, California: Model MLT.


Experiment Details

  1. Plants began as cuttings all taken at the same time and rooted in the same way.
  2. Once plants had three leaf sets specimens of equal size and development were selected for the side by side comparison.
  3. Plants were transplanted into 2 gallon plastic containers half the containers were filled with a popular indoor gardening peat mix, the other half were filled with GRODAN GROW-CUBES™. (3 plugs per container)
  4. Containers were all randomly placed under the same 600 watt light. Average temperatures in the room ranged from 65 to 80°F. Average humidity was 50%.
  5. Two of the containers were filled with media (one with soil, the other grow cubes) but no plants were inserted in these containers. Instead one irrometer device was placed in each. These containers did not have plants because the plants would create an added variable and this was designed to test the media not the plants.
  6. Plants were watered every three to four days as needed using filtered water at room temperature
  7. No additional fertilizer was added to the containers with the peat mix because the popular indoor gardening soil contains fertilizer already. The bag claims “no additional fertilizer needed for 30 days.”
  8. A simple base hydroponic nutrient was added to the water given to the grow cubes in a dosed amount equal to the strength of nutrients found in the peat containers.


Conclusion of experiment

The appearance of the plants in the experiment reveals significantly improved growth and development in those plants grown in GRODAN GROW-CUBES. The peat mix plants are healthy but their growth rate was considerably slower. Also, the GRODAN plant bloomed earlier and produced far more blooms than the peat plant.

When we examined the readings from the irrometer we found that the peat mix medium starts out immediately after saturation with a 2-3Kpa vacuum reading. This means that even after initial saturation plants must expend a large amount of energy to absorb the water from the peat mix. The GROW-CUBES have a vacuum reading of zero after saturation which means the roots can more passively absorb water and focus more of their energy on growth! (Note: Microbials in peat mixes do not change the vacuum readings).

As the containers with the irrometers begin to dry out we observed both medias increasing in vacuum as expected. The interesting thing was that at complete dryness the stone wool had less of a vacuum than the peat mix. This suggests that even when there is a little water left in a peat mix it is still pulls against the plant more than the stone wool at complete dryness.

Upon re-saturation vacuum pressure in the GRODAN GROW-CUBES quickly disappears while the vacuum pressure exerted by the peat mix slowly drops. In other words, the fresh food and water you give your plants are readily available much faster in GRODAN.


Take the GRODAN Challenge!

For those expert growers that only make changes based on experience, we encourage you to try this side- by-side experiment yourself. If you aren’t experienced with GROW-CUBES alone, try a 50% mix with your usual container medium in your first run. You will be amazed by the difference in growth!  Feel free to email for any advice or questions you may have.

“I used to be a confirmed peat grower; but that was before I tried GRODAN.”

“GROW-CUBES compacts far less than peat mixes, making them cheaper in use”

“Why drag home 40 lbs. of peat mix, when 5 lbs. of GRODAN does a better job?”

“GRODAN GROW-CUBES are designed to ensure plenty of air in the root zone at all times”

Peat versus GRODAN

Peat versus GRODAN