Glossary of terms and basic characteristics to be reported in scientific publications on growing media

In the research community of growing media and compost science, there is an increasing confusion related to inappropriate use of terms, and to a lack of description of minimal chemical, physical, biological characteristics of growing media for adequate data interpretation in scientific publications. A survey was conducted between the summer of 2019 and the autumn of 2020 among growing media scientists to help addressing these two issues. The first part dealt with a glossary of terms of importance that needed to be defined and clearly pointed to an agreement on most of proposed definitions. The survey showed clearly that a better definition of the following terms are needed: 1) hydroponics and soilless culture, 2) growing media components, especially peat itself, and 3) finally some basic characteristics of growing media. The second part surveyed the minimal characteristics to be given in papers, where respondents unanimously indicated that among chemical properties, pH and electrical conductivity should always be given. Meanwhile, most respondents expressed that nutrient concentration measured by medium saturated extract be given too. The following items were suggested to be “nice to have” for interpreting related data, although not “compulsory given”: exchangeable anions, cation, and anion exchange capacity, as well as CaCO₃ as indicated by a majority of the respondents. In terms of biological properties, a majority indicated that respiration rate and phytotoxicity tests should be reported. Some respondents suggested that indices of organic matter stability as well as C/N ratio should also be reported and colony forming unit counts and biological analyses would be nice to have. In term of physical properties, a majority indicated that air-filled porosity, easily available water, bulk density, total porosity, and hydraulic conductivity should be minimally given. Meanwhile, a majority also indicated that shrinkage, water retention curve, hydrophobicity test, relative gas diffusivity as well as unsaturated hydraulic conductivity curve should ideally be provided for better interpretation.