Utilising Sphagnum fibres as growing media for Pelargonium & Begonia

Peat is currently the most important raw material for growing media in horticulture. For a while now, alternative raw materials have been tested since there is a demand for more sustainable substrates for horticultural production. The aim of this research was to determine the effects of different Sphagnum L. biomass containing growing media on the vegetative and generative growth on Pelargonium L´Hér and Begonia L., and to determine how the different growing media affect the longevity of the plant in water deficit. There were two types of Sphagnum biomass used for the study and there were eight different compositions of Sphagnum based growing media in total. The growing media consisted of varying amounts of Sphagnum fibre and peat. Peat was amended with either 100%, 75%, 25% or 0% of Sphagnum fibre. 47 days from the beginning of the experiment some of the Begonias and Pelargoniums were transferred to a water deficit treatment in national plant phenotyping infrastructure (NaPPI) for non-destructive imaging. The results showed that the Pelargoniums cultivated in Sphagnum-based growing media had higher fresh and dry weights than the ones cultivated in 100% peat. With Begonia, there were no differences in fresh or dry weights of the plants between the treatments. The leaf areas were in trend with the fresh and dry weights. The higher the fresh and dry weights, the higher was the leaf area. There were no differences in the onset of flowering or the number of flowers in the plants between the different growing media for Pelargonium or Begonia. There were no notable morphological differences in the plants between the treatments either, which indicates that the Sphagnum fibre did not affect the ornamental value of Pelargonium and Begonia. In the water deficit treatment, there were no differences between the growing media in any of the values measured. The results indicate that the vegetative and generative growth of Pelargonium and Begonia on Sphagnum-based growing media was on acceptable level for production. Considering these results, Sphagnum biomass could be used in the growing media to replace peat, either partially or completely, for at least certain ornamentals