Institut für ökologische Chemie, Pflanzenanalytik und Vorratsschutz
During the last two decades, German growers continuously extended the acreage of potted herbs. Already one third of them is cultivated according to the EU regulations on organic farming and guidelines of organic certification bodies, respectively. However, in the last years there was a growing number of reports on inhibition of germination, chlorotic or necrotic cotyledons and reduced further growth. These damages seem to be associated with the growing medium and the fertilizer, and most cases have one thing in common: high amounts of ammonium in the growing medium. However, the ammonium itself cannot be the trigger of the damages, but it seems to be an indicator for a complex cause, which probably is linked to microbial processes in the growing medium. For growers as well as for manufactures of peat reduced growing media the uncertainty about the exact cause of the problem bear a high risk and deter growers from the shift from conventional to organic production. To avoid complaints growing media manufactures limit the percentage of peat substitutes to the minimum demanded by legislation and guidelines. The main aim of the project the identification of the mechanisms that leads to plant damage in organic production of potted herbs as well as the development of counteractive measures and avoidance strategies.
Federal Ministry of Agriculture, Food and Regional Identity
