Peat substitutes from renewable resources and landscape conservation materials
Since peat supplies in Germany and Europe are declining in the next decades, there is an urgent need for peat substitutes as growing media in commercial horticulture. All peat substitutes have to cope with adequate quantity in the long run and appropriate quality. Additionally, environmental requirements are becoming important. Therefore, we tested new peat substitutes from renewable resources (alder - Alnus glutinosa, cattail - Typha latifolia) and landscape conservation materials (composted heather - Calluna vulgaris) which combine the benefits and create synergetic effects between nature conservation and climate protection as well as with the interests of horticulture and agriculture sectors. Values of pH, salt contents, nitrogen, potassium and phosphorous contents of all three raw materials are in a favorable range for horticultural utilization. Concerning the water capacity, this was also the case for the variants with composted heather (50 and 100 Vol % peat substitute) and for the variants of alder and cattail (both 25 and 50 Vol % peat substitute). N immobilization was tested in variants with 25, 50 or 100% (Vol) peat substitute which showed no N immobilization for heather compost, a low immobilization for cattail and a high immobilization for alder. Despite N immobilization in some variants good results were obtained in growing tests with Chinese cabbage if fertilization was adapted according to the results of the N immobilization tests. In addition to these positive results in laboratory tests also promising results were achieved under practical conditions in three different nurseries specialized in the cultivation of vegetables, ornamentals as well as tree nursery plants. Therefore, the utilization of composted heather, alder and cattail biomass can serve as a peat substitute for commercial horticulture if cultivation conditions are adapted as indicated.
Leiber-Sauheitl, K., Bohne, H. and Boettcher, J. (2021). Peat substitutes from renewable resources and landscape conservation materials. Acta Hortic. 1305, 545-552
growing media, Alnus, Typha, Calluna, compost