Growing a sustainable future

With the global demand for new growing media expected to increase to 283 million m3 by 2050 (a figure that is some four times larger than the volume we currently have available to us), growing media manufacturers are continually exploring ground-breaking techniques – and investing in new, sustainable substrate material – to develop circular solutions for the controlled environment horticulture sector.

Supplying the industry with substrates that are both sustainable and a financially-sound option for horticulture sector is arguably not an easy task. But, as visitors to this year’s GreenTech Amsterdam could see, growing media manufacturers are continuing to trailblaze.

Visitors to Grodan’s stand, for example, were shown how the stone wool specialist is collaborating with lighting expert Signify to refine tomato cultivation. Last year (2023), the trial saw a combination of two irrigation treatments and the application of active dehumidification result in an impressive 50% less heat input compared to commercial reference growers. This year (2024), the research project hopes to further improve energy efficiency through the spectral dimming of the full LED installation, the use of innovative climate screens, and energy recovery from an active dehumidification system. Additionally, the trial will test new, adapted fertigation and irrigation management strategies. 

“When growing with full LED, another factor comes into play; steering your humidity to better manage the crop balance,” explained Marcel Raats, plant specialist for Philips LED grow lights. “With a holistic approach to growing; meaning separately managing light, heat, evaporation, fertigation, irrigation, and measuring and monitoring each factor, you will get the best insights in how the crop performs over time.”

Reduce the CO2 emission up to 80 percent

Other ways in which Grodan (and its parent company Rockwool) is reducing its energy usage includes the modification of two of its production lines in the Netherlands so that they can in the near future use innovative electric melting technology, which is based on low-carbon electricity. Upon completion in a few years’ time, the firm expects this investment to result in a fall of CO2 emissions of up to 80 percent for these two lines (and by more than half for the factory overall).

GreenTech Amsterdam visitors also learned that substrate supplier Kekkilä-BVB, owner of BVB Substrates, is actively ranking the carbon footprint of each of its substrates by giving them a ‘Future Fit’ score. 

Speaking during a discussion entitled Sustainable Growing Requires Sustainable Substrate, Nedeljko Basic – Kekkila-BVB’s Director, Portfolio Management – explained that, when creating sustainable substrate mixes, the raw materials are evaluated for how local they are to the grower, how they conserve water, how socially responsible they are sourced, their impact on nature (whether they are ‘nature positive’), their circularity, and their climate resilience. He asserted: “The location of the grower and also the production locations of the [substrate] supplier is really important.” Mindful of the need to create good value for the grower and the consumer, each material is also given a Fit for Purpose score based on its physical, chemical, and biological properties. He added that, when a mixture containing different materials is well-balanced, the plants can grow “even better than in a traditional substrates solution.” 

With demand for substrates increasing, Basic predicted that the complexity of growing media mixes is likely to increase in future. “We cannot expect that one material will save us and replace peat by itself.” As BVB develops its peat-free solutions, it’s busily sourcing new, sustainable raw materials, including Finnish reed canary grass (Phalaroides arundinacea). By spring 2025, harvesting of this type of reed grass will cover approximately 800 hectares, and by spring 2026, this is expected to increase to 1,700–1,800 hectares.

3D-printing by growers

Maan Biobased Products (part of Maan Group) and Klasmann-Deilmann together displayed their unique growing media solution, Nygaia, at this year’s GreenTech Amsterdam. The new substrate is made out of compostable, biodegradable polymers that mimic the growing media properties of peat. Nominated for a GreenTech Innovation and Concept Award, Nygaia is produced using state-of-the-art 3D printing technology. The goal is that, in the near future, growers will be able to 3D-print their own Nygaia growing media on site at their nurseries – therefore reducing transport costs and the overall carbon footprint of this innovative substrate. 

In a similar vein, Legro’s Botanicoir Precision Start (a new, premium peat-free coir) is available in environmentally-friendly BotaniCubes that come with biodegradable and compostable netting – allowing them to be potted directly. Botanicoir also produces its high-quality coir products with minimal environmental impact – employing techniques such as sun-drying for natural drying and biomass energy for mechanical drying, ensuring sustainability. To optimise water usage, it recycles water for its washing and buffering processes.

Meanwhile, with an increasing need to understand the physical properties of peat-free growing media such as coconut fibres, wood fibres, green compost, tree bark (which can have very different properties to traditional peat-based products), Eurofins Agro has this year (2024) expanded the capacity of its physical laboratory to help give growers insights into the nutrient and pH balance of their growing media.

And so, as the controlled environment sector continues to produce food and ornamental plants for the world’s growing population, innovative growing media companies are taking action to help growers do this as sustainably as possible.