A major challenge in the cultivation of perennial, flat-growing spice and medicinal plants is weed management. In practice, various strategies are applied on large and small cultivated areas. The Swiss Federal Office for Agriculture is now funding a new research project in which FiBL Switzerland, Agroscope Conthey and a group of herb producers are collaborating to evaluate the most efficient weed control methods. In order to obtain a national and international overview of applied weed control strategies, an extensive literature research and a national survey of 20 herb producers, as well as two experts in the field of non-chemical weed control, were carried out in a first step. The literature review collected 38 weed control measures, which were divided into four categories: traditional mechanical methods, advanced mechanical methods, robots and non-mechanised strategies (agronomic methods). The functionality, working speed, price, bio-suitability, general advantages and disadvantages, areas of application, as well as photos and references were documented for each method. In a face-to-face interview, all weed control measures in mechanised as well as in non-mechanised herb cultivation on each of the 20 farms were described. Of the mechanised farms (82% of respondents), most developed their own creative solutions, which are continuously adapted and improved. The majority use implement carriers or tractors with hitched machines from vegetable production technology. Depending on soil type, area size and slope of the plots, different strategies are followed. Above all, the choice of the following crop and the start of cultivation in spring was mentioned as a decisive strategy for good weed suppression, which reduces manual work and improves yields. After that, regular and consistent hoeing or harrowing is important. Winter preparation of perennial crops was also singled out as essential. The techniques used vary greatly depending on the producer, their experience and priorities. The producers are generally very interested in alternative weed control measures and in improving their methods. By combining the information from the literature research and the interviews, the most promising techniques will be defined in collaboration with the farmers at a roundtable in December 2021 and will be planned for on-farm field trials in 2022 and 2023. The aim is to formulate weed control recommendations for different crops in spice and medicinal plant production that are based on current standards and contribute to resilience, farm and production efficiency.
