In 2023 RHP certified plugs on the market


Nearly ten plug manufacturers have committed to the RHP certification process, which is expected to take 8 to 12 months. If the manufacturers successfully complete this process, they will be able to bring RHP certified plugs on the market at the end of 2023.

Last spring, experts from RHP, the knowledge centre for substrates, spoke with various producers and users of plugs and other preformed growing media about standardisation and certification. After two follow-up meetings and various company visits, it has become clear that certifying plugs is seen as useful.

Higher quality requirements

Customers are placing increasingly higher demands on quality, while there are currently few possibilities to bring certified plugs on the market. On the other hand, RHP's technical advisors are seeing increasingly larger and more complex claims in the cultivation of young plants. According to operational director Marco Zevenhoven, certification of plugs can limit damage cases. “Certification helps companies to achieve more consistency in quality, by setting quality requirements and making process agreements and and assuring these. Everyone benefits from that.”

RHP certification offers advantages

According to Zevenhoven, certification offers even more advantages for producers. “RHP has a product group structure in which affiliated, certified companies meet to discuss for example quality standards and sustainability. Plug manufacturers do not yet have a joint platform, while that has proven to be very useful after the meetings. There are plenty of challenges that you can better face together. If one company suffers from a fungus, it can also happen to another. Together you are stronger in the search for improvements.”

European legislation

New methods are being developed in the project. In order to make it possible to test plugs according to the new European fertiliser legislation - which includes growing media - this project also establishes the volume measurement and a method to determine the dimensions. According to Gerrit Wever, technical advisor at RHP, these are essential for European legislation.

Careful testing, standardising, checking

The next meeting of RHP experts and plug manufacturers is scheduled at the end of October. In the meantime, RHP is conducting tests with plugs to develop standardisation of measurement methods. A proposal is also being made for establishing the standards including physical and chemical requirements that plugs must meet for the RHP quality mark. The certification of raw materials and products is a careful process, in which the independent Technical Committee and the Central Board of Experts play an important role. They check the content of the proposals of a working group consisting of producers, users and RHP experts.

Project coordination is done by Daisy Otto, e-mail:

More news? 

show all items
//Enable form button reCAPTCHA