In a 2-year field experiment a comparison was made of the effect of sowing dates on growth and yielding of two cultivars of blueweed: Blue Bedder and Mixed Bedding. The seeds were sown in mid April and at the beginning of May, at the rate of 5kg∙ ha-1 in rows 45 cm apart. The earlier date of sowing appeared to be more favourable for both cultivars: the plants were higher, had more branches, and produced greater mass of aboveground parts, roots and seeds. Delay of sowing resulted, however, in better germination of seeds and caused a slight increase of fat content in yield of seeds. As concerns the cultivars compared, irrespective of the date of sowing the plants of Mixed Bedding were higher, produced more vegetative mass, and had slightly more fat in seeds than Blue Bedder.