Organic seedling production

Organic seedlings have to be produced in accordance with the rules laid down in EU Regulations. However, production protocols are needed to ensure the efficient use of inputs. The characteristics of growing media and nutrition are the major factors that affect seedling quality. The aim of this research was to test locally available substrates in growing media and organic fertilizers in order to improve alternatives to peat that could be applicable at the commercial level to produce organic watermelon ('Asbal') seedlings. In two successive experiments (Exp. 1 and 2), peat was compared with different media composed of local peat, perlite, composted farmyard manure, clinoptilolite and vermicompost. The results of ten tests on germination rates, and shoot and root fresh and dry weights, showed that vermicompost if used alone is not appropriate. Four growing media, selected by their performance on seedling biomass in Exp. 1 and 2, were used to compare different fertilization programs in Exp. 3 and 4. Three nutritional programs, namely liquid vermicompost, diluted poultry manure, and liquid composted farmyard manure were tested with the four growing media namely (1) peat, (2) 60% local peat+40% vermicompost, (3) local peat + perlite + vermicompost and (4) local peat + clinoptilolite + vermicompost. The growing medium composed of local peat and vermicompost was found to be as good as peat in terms of shoot fresh and dry weights when fertilized with diluted poultry manure in organic watermelon seedling production. © 2017 ISHS.