Armin Blievernicht, Stefan Irrgang, Matthias Zander, Christian Ulrichs
Proceedings of the 14th International Peat Congress
growing-medium, peat-moss, plant-production, sphagnum
Theme V. Restoration, rehabilitation and after-use of disturbed peatlands
In the European Union, about 29 million m3 of peat IS used for the production of horticultural growing media every year. Due to its outstanding properties, peat is still the main constituent for growing plants in pots, but it is a diminishing resource. Over the last decades, no viable alternatives for reducing the major proportion of peat in growing media have been found. White peat mainly consists of slightly decomposed peat mosses (Sphagnum sp.). Preliminary tests with dried non-decomposed Sphagnum biomass indicate that decomposition is not necessary for peat moss to be a perfect constituent of growing media. Thus, we devised a production method for peat mosses on artificial floating mats. After one year of cultivation, the average harvested biomass of Sphagnum fimbriatum was as high as 5.4 t ha-1 dry weight. Currently, our peat moss production on open water systems covers 2,000 m2. Investigations with different Sphagnum-based growing media led to a product which is made of 70% (v/v) dried Sphagnum biomass. On a large scale, this new growing medium has been tested in the commercial production process of an ornamental plant company. Three tested Euphorbia pulcherrima cultivars showed a similar plant growth in the new growing medium compared to the peat-based control. Due to potential upcoming regulations for extraction and use of peat, the younger non-decomposed Sphagnum appears as a promising alternative and will be investigated in more detail.