The characteristic growth features of four Welsh onion cultivars (‘Parade’, ‘Performer’, ‘Siedmiolatka Zielona’, and ‘Siedmiolatka Czerwona’) dependant on growing method (seeds sown directly in the field and from transplants) were evaluated during the three-year study (2007-2009). The following traits were determined: plant height, number of leaves on a single plant, tendency to produce laterals, plant weight, as well as length and diameter of the pseudostem. Plants of the ‘Parade’ cultivar were the highest (76.0 cm, on average), while those of ‘Siedmiolatka Czerwona’ were the shortest (mean 68.6 cm). Pseudostem length was found to be the main factor determining the height of the Welsh onion. The longest pseudostems were observed for the ‘Parade’ and ‘Performer’ cultivars, while the ‘Siedmiolatka Czerwona’ had the shortest. In each of the tested cultivars, those grown from a transplant resulted in larger pseudostems and a larger number of leaves. Amongst the studied cultivars, ‘Siedmiolatka Czerwona’ had the most numerous leaves and laterals (45.2 leaves and 14.3 laterals, on average), while ‘Performer’ and ‘Parade’ had the least (mean 11.7 and 14.8 leaves and 2.4 and 2.6 laterals, respectively). The weight of a single plant with laterals significantly differed depending on the cultivar and growing method. At the end of the vegetation period (mid-October), the ‘Parade’ and ‘Performer’ cultivars grown from transplants were characterised by the highest weights (mean 518.2 g and 631.7 g), while ‘Siedmiolatka Czerwona’ and ‘Siedmiolatka Zielona’ grown from seeds had the lowest (222 g, on average).