Coriander (Coriandrum sativum L.) is known as a herbal plant all over the world. The yield of coriander fruit is influenced by weather conditions, agronomic and genetic factors. This paper discusses the impact of the year of research and date of sowing and their mutual interactions on yield and yield components of coriander and on the content and chemical profile of essential oil in coriander fruit. It has been demonstrated that air temperature and precipitation during each season had a determining effect on coriander fruit yields and yield their component. The weather conditions in 2007 were most favourable for the growth and development of coriander, which then produced the highest fruit yield (1.54 toha^-1). The date of sowing did not differentiate yields of coriander. However, yields of coriander were determined by interaction of sowing date with years of research. In north-eastern Poland, a date of sowing which falls between April 10 and 20 seems to ensure best coriander yields (1.40 taha^-1). When coriander was sown later, the yield tended to be lower. Coriander yielding was positively correlated with the weight of fruit per plant. The content of essential oil in coriander fruits was distinctly different between the years of the experiment. The content of oil in coriander fruits was slightly raised by a later sowing date. The main component of coriander essential oil was linalool, which made up 65–67% of its chemical composition. The year of the experiment rather than the date of sowing differentiated the composition of coriander oil.

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