Tulips belong to one of the most important bulbous plants from the economic point of view. Bulbs are reproduced in order to force for cut flowers. The biggest problem for the Polish producers is to obtain high yield of good quality bulbs, so that it is advisable to verify other than traditional methods of cultivation. The field experiment was conducted in 2006–2009. ‘Ballerina’ tulips were cultivated with a traditional method flat and on the ridges. Bulbs were planted at the depth of 9, 12, 15 and 19 cm. Cultivation methods used in the experiment did not affect the length of tulips flowering shoots. Tulips cultivated on the ridges produced longer tepals. Flowering shoots and tepals were shorter in case of tulips cultivated at the depth of 19 cm in comparison to those cultivated at the depth of 9–12 cm. Cultivation on the ridges led to production of 7.5% more of daughter bulbs and 8.2% of commercial bulbs. Weight of daughter bulbs was higher in ridge cultivation on average by 10.8%, and the weight of commercial bulbs on average by 14% in relation to flat cultivation. Cultivation on the ridges also increased the amount and weight of first grade bulbs (of circumference of >12 cm) by respectively 19.5 and 23.3% in comparison to traditional cultivation. The highest yield of commercial bulbs in ridge cultivation was obtained when bulbs were planted at the depth of 12–15 cm. In flat cultivation, greater amount and weight of commercial yield bulbs and first grade bulbs was obtained by planting tulips at the depth of 15–19 cm. Cultivation on the ridges ensures better aeration of soil, what results in smaller share of bulbs infected with pathogens in the total yield, in comparison to flat cultivation.

97-110