Improving Physical Properties of Plant Growing Medias Using Perlite

Abstract

The most widely used growing media in the production of potted ornamental plants is peat. However, the studies for alternative solutions are being conducted due to the reasons such as restricted peat sources, high cost, destruction of natural environment due to peat production and variability in the quality of produced peat. In the relevant literature, there are two basic ideas on which the studies have focused on. The first one is the development of new growing media using organic-origin wastes, the second one is the preparation of the mixtures in which organic and inorganic materials are used as a component of growingmediums. In this study which was prepared in parallel with the relevant main ideas in the literature, the effects of perlite utilization on the physical properties of indigenous peat, and on those of the growing media obtained from hazelnut cinder, which is among agricultural organic materials in our country and has considerable  potential to be the most important alternative of peat, were investigated. For this purpose, the physical properties of the growingmedias, prepared by mixing perlite with raw peat and hazelnut husk, at various ratios (10,15,20,25%), were investigated, and the results obtained were compared with sphagnum peat, and with desired properties for ideal growingmedias, in the literature. When the results obtained from the study were examined, it was seen that as well as the highest values were observed in the mixtures using 25% perlite, the perlite addition increased the porosity of raw peat by 68.25% and air capacity by 30.03%, and that the hazelnut husk decreased air capacity, higher than the ideal values,  by 47.19%,thus approximating it  its ideal value range. With increasing perlite ratio in the mixtures, the organic substance contents and water holding capacities of the growingmedias decreased as their pH values increased. However, in applications using 25% Perlite, the shrinkage rates of raw peat and hazelnut husk were found as 17.05% and 6.41% respectively,  and the water resuction times of those were found as 1.52 and 1.21 minutes, respectively. Based on these results, it can be said that the most important contribution of perlite utilization for raw peat and hazelnut husk is to decrease shrinkage rates and water resuction times, and that this improvement will avail in preventing the damages that occur in plant roots due to  drying and shrinking of the growing media, and in decreasing  the irrigation frequency.