What is an RHP certification?

We supply vermiculite with the RHP certification. What does this certification mean actually?


Regeling Handelspotgronden (Potting Soil Trade Regulation) is the European knowledge centre for substrates. They certify substrates with the RHP certification. The RHP certification guarantees that the substrate meets the relevant quality requirements for, for example, water absorption, air content, pH and nutrients.  It also provides more certainty that the substrate is clean and pure, and can be used safely without risks to the crop.

Quality, health and the environment

The raw materials of RHP-certified substrates are examined beforehand for weed seeds, etc. Stringent tests are also carried out for heavy metals and pathogens dangerous to plant and man. Producers work with a respect for the environment.

Logo on packaging

You can recognise a substrate, such as potting soil, by the logo on the packaging. This logo guarantees that the product contains RHP-certified raw materials.


We supply vermiculite with the RHP certification. In agriculture it used mainly as a growing and topping medium. It keeps the soil airy and ensures for an optimal air-water balance. Young cuttings have vermiculite added to the soil. The upper layer of the potting soil then dries less quickly and an optimal growing climate is created.

Each plant has its own set of requirements for optimal growth. Choosing a safe potting soil is a first important step. The RHP certification guarantees the quality of the vermiculite that we supply.

Kim Oosterom, Account Manager Houweling Group