Innovative growing media for horticultural nursery

Peat is a traditional growing media that is considered the best option to gain the optimum quality and yield for horticultural seedling production and ornamental plants. In fact, efficient production of horticultural seedlings in nurseries requires plants that can develop rapidly and uniformly, and the peat results ideal for this purpose, thanks to its appropriate physical, chemical and biological characteristics (Bures, 1997). However, the cost of high quality peat for horticultural use, together with the declining availability of peat in the near future, makes it necessary to look for alternative materials. Moreover, in a policy of recycling and reusing, various organic residues produced by agriculture, livestock farming, forestry, industries and town, have been considered as possible alternatives to replace peat for growing media preparation. In this study, for this purpose, three organic materials are chosen: coconut fiber, digestate and biochar, and their main chemical, physical-chemical and hydraulic properties were evaluated. Mixtures of these materials are tested to evaluate their ability to replace, totally or partially, peat as growing media, testing their agronomical performance on seed germination and seedling growth of six vegetables species used worldwide for domestic and commercial purposes: tomato, pepper, lettuce, cauliflower, fennel and basil. Based on the research results, it was concluded that digestate and coconut fiber mixing with peat and each other could be used in the cultivation of the tested horticultural crops. Biochar, indeed, in trend with its intrinsic properties, different from coconut fiber and digestate, would be acceptable alternative to peat when used at an advanced stage of plants development and in bigger container, as in the case of basil.