Experiences and challenges of organic cultivation of medicinal and spice plants

Medicinal and spice plants are risky crops. In comparison to the agricultural main crops, there is a strong fluctuation of the yields and the expenses are much higher. The risk increases if the crops are organically cultivated due to the restrictions of the use agro-chemicals. The organic farm Marold is located in Thuringia and grows 70 minor crop species on 340 ha of predominantly loess soil. Grass-clover in the crop rotation and well prepared manure with as little as possible weed seeds ensure the nitrogen supply of the plants. Couch grass and thistle require a special strategy of weed control. Seed weeds can be controlled by prophylactic measures in the crop rotation and soil management and by maintenance of boundary ridges. The expense of manual labour can be reduced by minimising the width of the band of the row with the crop plants which can not be covered by the tools of the hoeing machine. The seeds used for drilling crops should not be infested by diseases. Umbel diseases of fennel, coriander and caraway provoke severe yield losses up to 40%. The most important pests are field mice (in biennial caraway), blossom rape beetle (in Brassicaceae) and aphids. Systematic investigations for the development of effective plant protection method for organic cultivation are required.