Netherlands: Substrate and cultivation inseparable

"An alternative to purification is emission-free cultivation. From trials we know that this is cheaper, more sustainable and possible without production loss. However, among growers the notion ‘how to purify’ is still often leading, not 'how to manage risk’ and ‘what does the plant need'." This was said by Eelke Hempenius from Grodan, one of the speakers at the recent Substrate Knowledge Day in Bleiswijk, the Netherlands. "With conventional techniques like the use of low-sodium irrigation water, effective disinfection with UV, ozone and heating, and steering based on plant absorption instead of drainage, the grower can make great strides. Why this doesn’t occur has a lot to do with conservatism. Awareness of the possibilities needs to increase and the grower must dare to step out of his comfort zone."

Every grower knows that substrate is more than a bit of coco or rock wool, but he can probably use all the help he can get when it comes to reducing chemical crop protection products and emission-free cultivation. This is why this fifth biannual Substrate Knowledge Day – organized by the Dutch Association of Potting Soil and Substrate Manufacturers (VPN), the knowledge center in substrate and soil improvement materials (RHP) and Wageningen UR Greenhouse Horticulture – was given the theme “Expansion and support of substrate cultivation”. Besides Eelke many speakers tackled topics from different perspectives, such as risk management, new measurement methods of various nutrients and materials, assorted cultivation trials, projects in other countries and the processing of different components such as biochar and bio-fertilizers in substrate.

The diversity of topics made the afternoon a treat for the experts. Substrate producers, obviously well-represented, and people from the world of research and technology often went in-depth into new research and insights. This did somewhat detract from actual implementation and ready-to-use cultivation advice. An interim round of questions whereby the audience could vote live via smartphone revealed that things like emission-free cultivation and chemicals discharge was still primarily seen as a grower 'problem' and less as a problem of the sector as a whole.

But this wasn't all that was discussed during the afternoon. Substrate is largely connected to steering production, making disease pressure and plant resistance manageable, and increasingly efficient use of raw materials – in various crops and worldwide – which makes the development of new materials and techniques an absolute must.