Compost as growing media component for salt-sensitive plants

Abstract

Composting has been considerably recognized as a viable management method for solid organic wastes aimed at recycling of its end-product as a potting substrate for ornamental plants. Pelargonium and Salvia as salt-sensitive plants were grown in the mixture of compost (75, 50, 25% by volume) and additives (Hygromull, Cocofiber and SPS-standard soil type 73 with 70% peat and 30% clay). Since plants may suffer from a high salt content, thus in a further experiment compost was added as a partial substitute for peat. The results of the first pot experiment reveal that the large percentage of compost in the substrate had negative effects on plant growth and nutrient uptake (N, P, K and Na). Both yield formation and nutrient uptake significantly increased and almost gained levels of those in the control in the second pot experiment when plants were grown in peat-based substrates. Especially, the growth of Salvia was significantly improved. Consequently, the compost-based media (> 50% volume of compost) cannot be recommended for salt sensitive ornamental plants, while less than 25% of compost incorporated into peat creates peat-based substrates which reasonably enhanced growth of Pelargonium and Salvia.