What is sustainable growing media?
Our aim is to make environmentally friendly substrates, but how can we determine what is green?
We look at the whole lifecycle from where materials are sourced, to how they are transported, to what is being done with them after use.
Using this method, we are able to create specific targets, identify areas for improvement, and recognize even small changes that can make a big difference.
What materials do we use?
When evaluating which materials go into our substrates we not only look at their unique characteristics such as water hold or air capacity, but we also take into consideration their environmental impacts.
|+ Possess excellent physical, chemical and biological properties for plant growth
+ Safe in many ways: no human pathogenes,
no pesticides, very low plant pathogenens,
no fertilization issues, good food safety
+ Usable for acidic plants
+ Peat is an extremely well understood, reliable
and consistent option for many growers
+ Harvesting under very strict environmental regulations
+ Excellent availability
|– Low re-wetting capacity
– Peatland growth is slow
(~1 mm per year)
|+ Renewable material
+ Good structure and stability
+ It provides a favorable balance of air and water to plant root
+ High re-wetting capacity
+ Holds its structure well
+ Low bulk density
|– Treatment needed to prevent release
of phytotoxic levels of salts
– Cleaning and buffering is a water
– Through processing, higher risk for
phytosanitary and chemical pollution
– Nitrate and other salts will come into
the environment because of the buffering treatment
|+ Renewable material
+ High total porosity and air
holding capacity after treatment
+ It is used to optimize the
physical properties of other
material components (e.g.
reducing bulk density and
increasing air space)
|– Need of fertilisers, especially itrogen, is higher when using wood fiber
– Rarely used as a stand-alone growing media component because it retains insufficient plant available water and has a tendency to become compressed
|+ Composts are high in nutrients
+ Composting allows for the re-use of many waste materials that would otherwise end up in landfill or
+ Composts can support in
|– High bulk density (70–85%
of the consists of minerals)
– High pH and nutrient levels (mainly
potassium and phosphorus)
– Requires other materials to
operate (usually peat
– Prone to contaminants
|+ Good structure for long period
+ Good drainage
+ It has a high air capacity
+ Excellent for epiphytes
|– Very low water holding capacity
– Secondary treatment needed to make sure
no pine tree nematodes are transported
– As a waste product its physical, chemical
and biological properties can vary
– Use in low amounts in mixture
– Nutrients mainly potassium, sodium and chloride
– Growth inhibition when used in high amount
|+ Excellent balance of humidity and airiness
+ Very low bulk density
+ Low pH and nutrient level
(easy to adapt to the needs of different plants)
+ Very easily available water
|– Production capacity
dependent on timely requests
– New material, less experience
Peat in our growing media
Peat is a unique organic raw material, formed of partially decayed vegetation in wetlands. It’s classified as a slowly renewable biomass source (The Intergovernmental Panel on Climate Change – IPCC).
Why do we use it?
Peat is the safest, purest and most-used raw material for growing because it:
- Contains no weeds or pathogens
- Improves soil structure
- Increases water retention
- Helps to reduce leaching of nutrients
- Is highly tolerant of pH variations, so it improves soil buffering capacity
- Enables us to trial and use new circular and renewable materials
Future of growing media
To meet the challenges of the 21st century, the amount of growing media will need to increase by 332% over the next 30 years*. At the same time, there will be less resources such as water, arable land, and various materials. In order to tackle this problem we have started the Grow Together Programme. The programme consists of our internal research projects as well as collaborations with customers and research institutes to investigate and develop new ways of growing sustainably, by utilising and optimising our current materials throughout their lifecycle, as well as exploring potential new alternatives.
*Source: Growing media for food and quality of life in the period 2020-2050, Professor Chris Blok et al, Wageningen University & Research, 2020
Growing Media Community
If we want to secure a happy and healthy future for people and planet, then collaboration is essential. Our growing media community is not just made up of growers and innovation partners, but we also have to work along side our competitors so we can share knowledge to help the public and decision makers understand the world of horticulture.