13 march 2026
The introduction of the prescription for growing media (accompanying the delivered product) will start soon. RHP, knowledge centre for substrates, has developed this prescription in collaboration with affiliated, certified substrate producers. The aim is to provide an objective and practical tool that supports representatives in their conversations with growers about growing media containing, for example, renewable raw materials. The prescription is intended to make growers aware of the points of attention related to the use of the supplied substrate.
RHP certified substrate is composed with the utmost care and meets strict quality requirements. When a substrate is delivered with a prescription, this means that there are points of attention for growers during the culture that differ from what they are used to with growing media based on traditional (peat) raw materials. The prescription clarifies which properties of the substrate require extra attention. This helps growers to better understand what to expect when using the substrate and how to take these aspects into account during cultivation.
The prescription accompanying the delivered substrate serves as a clear information sheet explaining the properties of that specific product. A QR code provides access to the RHP website for additional explanation of the points of attention mentioned in the prescription. These points of attention, including the extent to which they are relevant for the culture, are determined using a calculation model that is linked to the prescription. This model will be introduced in a simplified form and will be further developed in the coming period.
The prescription is designed as a practical conversation tool for representatives and as an information source for growers. It provides an objective and clear understanding of the properties of the delivered substrate – including those containing renewable raw materials – helps to manage expectations, and explains where and how these properties may differ from what growers are used to. The prescription offers clarity on possible changes when a substrate recipe has been adjusted, and supports representatives in discussing which adjustments growers themselves can make to keep their culture successful. This gives growers a better understanding of what to expect when using the substrate and how the prescription can support them in achieving optimal cultivation performance. In this way, the prescription forms a bridge between producer and grower.
To use the prescription effectively in conversations with growers, representatives of substrate producers initially need substantial knowledge. The representative must be able to explain the content of the prescription, interpret what changes mean for a culture and answer growers’ questions. Product managers and quality officers also play an important role in this. To ensure that all those involved can use the prescription as a valuable communication tool in contact with growers, RHP is organising a webinar series on 23 April and 26 May. Certified substrate producers will soon receive an invitation email with registration options.
Working Group Prescription, from left to right: Joy Godrie (Klasmann-Deilmann), Ronald Keijzer (Lensli), Gerrit Wever (RHP), Ivo Breugelmans (MeeGaa Substrates), Bram van Bommel (Kekkilä-BVB).
