Branch organisations and certificates

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Branch organisations and certificates

Our Precision Growing strategy has evolved over several years via ongoing input from a variety of external stakeholders including growers, retailers, non-governmental organisations (NGO’s), scientific researchers and policymakers. We are also an active partner in many industry associations and other groups who share a common focus on the latest developments and trends in the sector. We play an active role organising and participating in many events providing specialists to share the latest knowledge with a wide audience. We are member of the following branch organisations:

EU Ecolabel: the guarantee of sustainability

In 2008, Grodan was the first stone wool growing media manufacturer to be awarded the European Ecolabel, the EU’s seal of approval for non-food products. This demonstrates that Grodan products comply with the European environmental criteria for growing media of mineral origin, such as stone wool. In complying with these criteria, the raw materials must originate from properly licensed and responsibly managed sources and in addition, products must contain at least 30% recycled content. Furthermore, energy consumption and atmospheric pollution during manufacturing must comply with strictly monitored limits, products must satisfy the highest health and safety standards for stone wool materials and ambitious targets for the recycling of products must be met. Finally, products must also undergo testing using specific methods to guarantee their performance as growing media for plants. Manufacturers are obliged to make Information available to users and on product labels. The EU Ecolabel for Grodan growing media applies to its use in professional horticulture. Our products comply with the specific demands of the EU Ecolabel as follows:

  • Product pH, test method EN 13037 (using nutrient solution): pH 6.0 – 6.5
  • Product EC, test method EN 13038: 10-25 MS/m
  • Germination and growth inhibition, test method EN 16086-1: no abnormalities

Since the EU Ecolabel imposes environmental and quality requirements, it offers customers both guaranteed sustainability and guaranteed quality: this seal of approval demonstrates that supplying both quality and sustainable products can be achieved through compliance with the EU Ecolabel standard.

Visit EU Ecolabel


AVAG is the leading trade organisation for contractors and fitters in glasshouse horticulture in the Netherlands and promotes the joint interests of affiliated members and fosters glasshouse horticulture in the Netherlands and abroad.

Visit AVAG


Putting Food Safety and Sustainability on the Map G.A.P. stands for Good Agricultural Practice – and GLOBALG.A.P. is the worldwide standard that assures it. GLOBALG.A.P. members create private sector incentives for agricultural producers worldwide to adopt safe and sustainable practices to make this world a better place to live in for our children.



RHP has been the European knowledge centre for growing media since 1963  RHP certified substrates guarantee an optimal start of the culture. The RHP quality mark guarantees that the substrate meets the right quality requirements for water and air content, pH and for example EC. It also guarantees that the substrate is pure and clean and that it can be used without risks for the culture. The RHP quality mark guarantees the quality of growing media in the chain, from raw materials production until processing and delivery at the company of the user.

Visit RHP


The VPN is the industry and interest organization of the Dutch substrate sector. The VPN and its members stand for high quality substrates, which are a prerequisite for healthy growth of all plants.

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The Organisation of Horticultural Consultants and Researchers

The Organisation of Horticultural Consultants and Researchers (OVTO) is an organisation for service companies, which specialises in consultancy and research in and around the horticultural sector. The association was founded in 1985 and now has 21 members with about 200 consultants and research workers. The members with their consultants are mainly active in the Dutch greenhouse industry, though OVTO members are increasingly often offering their services to other horticultural sectors and abroad.

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Delphy stands for Worldwide Expertise for Food & Flowers. Through this, Delphy is the company in knowledge and expertise for our partners in plant sectors, worldwide. The knowledge experts of Delphy contribute to the success of our partners thus creating their own success.

Visit Delphy