The Character of Composted Bracken (Pteridium aquilinum L. Kuhn) and its Potential as a Peat Replacement Medium

The preparation of natural bracken (Pteridium aquilinum L. Kuhn) from the field to a compost suitable for acid loving plants is described. Key chemical and physical characteristics of the compost were determined by laboratory assessments of particle size, pH, air filled porosity (AFP), water retention characteristics, nitrogen draw down index (NDI) and basic chemistry. The procedure to ensure the breakdown of Ptaquiloside carcinogens is discussed. The material is naturally N poor, K rich with pH < 5.0, at cutting. During composting, particle size declines but pH naturally rises. Options to retain low pH and improve the water holding capacity are discussed. Nitrogen lock-up is similar to peat, but conductivity is lower, making nutrient management of pot plants easy. Water management is the key to successful use in the nursery. This plant is a highly sustainable resource, regaining biomass if cut in alternate years, growing along the western oceanic areas of Europe, particularly on light acid soils, from Norway to Spain and from Ireland eastward beyond Germany.