| 1. Introduction Essential oil is one of the many products people may gain from hemp (Cannabis sativa L.). It contains many volatile compounds, mainly monoterpenes and sesquiterpenes, a small number of higher terpenes and some other terpenoid like compounds (Turner et al. 1980) obtained by steam distillation. It is used for cosmetica, as an additive to food, in aroma therapy and in the future it may be of interest to the perfume industry. It is also reported to have some pest controlling properties against bacterias (Fournier et al. 1978, McPartland 1997), insects (McPartland 1997) and probably even against some plants (Pate 1994, McPartland 1997). Production of essential oils from hemp is rather rare. Its sales potential is not clear yet and at present it is not more than a niche product. In Switzerland some farmers produce essential hemp oils since 1995. They are interested in the agronomic factors influencing its yield and quality. Mediavilla and Steinemann (1997) studied the influence of the strains. As known for other plants harvest time may have important consequences to essential oil production (Husain 1994). In addition plant density and even pollination may influence buds yield and thus essential oil yield. 2.Material&Methods | 3.Results | 4.Discussion | 5.Conclusions | 6.References | 7.Acknowledgements |