Marco Zevenhoven is the operational Director at RHP. He has over 35 years of working experience at RHP, the knowledge center and quality mark for substrates. Nowadays he is operational director. Before that he worked as technical advisor and travelled the world to visit producers of growing media and their suppliers. The products and processes in the entire chain of the growing media industry hold no secrets for him. Nevertheless, the industry and also growers are facing major challenges with the increasing use of renewable raw materials. For many years RHP is working on extensive research into renewable raw materials and new growing media. Marco is closely involved in the raw materials transition, based on his expertise in the field of safety and quality. Also the two pillars of the RHP quality mark, which is considered the world’s most stringent quality standard for the growing media industry. Marco is jointly responsible for the quality mark requirements and the coordination of various international product groups that are active within RHP.