Somewhere around the middle of the twentieth century, the research station (Proefstation) Naaldwijk played the initiative role in the field of quality control of potting soil
Also the research station in Aalsmeer drew up a regulation. In 1963 a unique cooperation between the research institutes and information services of the authority and business, that was occupied with the excavation of raw materials and production of potting soil came into existence. This cooperation resulted in the establishment of a national regulation: Regeling HandelsPotgronden, RHP. When the authorities distanced themselves from direct involvement in the cooperation, the regulation was privatized in 1986 and converted in stichting RHP.