The present experiment was performed on Hymenocallis speciosa Salisb. plant throughout two successive seasons (2011/2012 and 2012/2013) at the nursery of Horticulture Research Institute, ARC, Giza, Egypt. The aim was to quantify the water requirements of Hymenocallis speciosa Salisb. plants grown in different growing media, i.e. clay, sand/clay, sand/compost (2:1, v/v) and sand/sewage sludge (4:1, v/v) with supplying the plants with different irrigation levels (low, moderate and high) according to field capacity of each growing medium used in every irrigation to asses the most suitable irrigation level for producing the best vigorous plant growth as well as for reducing the amount of water used in agricultural production and determine the best growing media used for producing plants with high yield and quality. Accordingly, bulbs of an average weight of 46 g and 10 cm diameter were selected and planted on March 12th in plastic pots of 30 cm diameter under open field conditions in both seasons. The results emphasized that sand/compost (2:1, v/v) was the best medium used for improving vegetative growth and root parameters as well as most flower traits, bulbs productivity and chemical constituents of plant leaves and bulbs. Besides, it proved its mastery in shortening the time required from planting to flowering. Meanwhile, sand/clay (2:1, v/v) and sand/sewage sludge (4:1, v/v) were less efficient in improving plant traits and occupied the second and third ranks, respectively. In contrast, clay medium gave the least efficiency in this concern comparing with the other media used in the two seasons. Also, great influence was noticed on the above mentioned traits due to supplying plants either moderate or high level in every irrigation. Meanwhile, the lowest irrigation regime gave an intermediate effects on the same traits.
Therefore, and from the interaction it could be recommended to use sand/compost (2:1, v/v) medium in plantation with supplying plants the moderate irrigation level in every irrigation for achieving high plant quality of Hymenocallis speciosa Salisb. plant, besides save a good deal of water for other purposes.